The purpose of this article is to provide information on assessing physical and cognitive aspects for those affected by long COVID that may impact on work ability, and to provide an insight into rehabilitation as well as possible workplace adaptations. More information on adapting the workplace and protecting workers from COVID-19 and its consequences, as well information on measures to address limitations imposed by Long COVID at the workplace can be found in previous guidance for workers and employers.
This document provides links to relevant information from EU-OSHA and includes a list of resources from various providers regarding different aspects of cognitive and physical rehabilitation for workers that experience long COVID symptoms.
Recognising Long COVID and identifying its implications for work ability
Following the COVID-19 pandemic, a considerable number of patients showed longer-lasting health problems persisting for months. While COVID-19 primarily affects the respiratory system, these symptoms are not necessarily restricted to breathing and lung function in general. Post-COVID Conditions (PCC) or, interchangeably, long COVID, as it is known, refers to any symptom or medical condition that may develop after a SARS-CoV-2 infection. It includes a wide range of symptoms or conditions that may improve, worsen, or be ongoing. Previous infections may have been recognised or unrecognised.[1],[2] Long COVID is recognised as a formal medical syndrome and there have been continuous efforts to define the condition [3],[4]. According to the ICD-11[5], an international classification of diseases by the World Health Organization:
“Post COVID-19 condition occurs in individuals with a history of probable or confirmed SARS CoV-2 infection, usually 3 months from the onset of COVID-19 with symptoms, and that last for at least 2 months and cannot be explained by an alternative diagnosis. Common symptoms include fatigue, shortness of breath, cognitive dysfunction but also others, and generally have an impact on everyday functioning. Symptoms may be new onset following initial recovery from an acute COVID-19 episode or persist from the initial illness. Symptoms may also fluctuate or relapse over time.”[6]
Characteristics, signs, and symptoms of Long COVID
Is Long COVID a common condition in those recovering from COVID-19?
According to a meta-analysis by the European Centre for Disease Control (ECDC), the prevalence of any long COVID symptom is 51% percent in people that had suffered COVID-19 but were not hospitalised. This may be an overestimation, as undiagnosed conditions may also be attributed to a recent history of COVID-19.[7]
Who is vulnerable?
Figure 1. A non-exhaustive list of COVID-19 symptoms. Source: George D. Vavougios
Long COVID includes a wide variety of signs and symptoms. Currently women at working age and those that had experienced severe COVID-19 may be at an increased risk of developing long COVID, especially those who were hospitalised or needed intensive care. People with underlying health conditions may also be at risk.
How long does long COVID last?
The duration of each symptom may range between several days to months, or in some cases, years. Long COVID may follow several possible clinical courses. It may resolve completely, result in residual disability, or progress with relapses. Effective forecasting of who will experience what and for how long is not currently possible.
What are the signs and symptoms of long COVID?
Long COVID can affect virtually any aspect of human health, and essentially any organ. As many as 200 symptoms and medical conditions have been described[8]: A non-exhaustive list of long COVID symptoms is presented in Figure 1.
Does long COVID affect work ability?
Long COVID is a condition that can lead to significant disability, negatively impacting quality of life and greatly diminish one’s physical and mental capacity. The impairment brought by long COVID, whether temporary or permanent, is capable of significantly affecting a person’s ability to work. EU-OSHA has raised specific issues regarding the impact of long COVID and occupational health and safety[9]:
Workers with long COVID may suffer functional impairments and disability, hindering both their private and social lives, as well as work.
Long COVID-associated disability may result in diminished capacity to perform work-related tasks or becoming physically and mentally unable to work.
Safety critical issues may arise in undiagnosed long COVID, e.g., errors when handling heavy machinery, balance problems in workers operating at greater heights, etc.
Access to occupational health and rehabilitation services may be unavailable, and thus avoidable work losses may occur.
Comprehensive assessment and rehabilitation by a multidisciplinary team may be required to effectively recover from long COVID and restore work ability. Post-traumatic stress symptoms have also been identified in COVID-19 survivors.[10]
Informing the workers, organisations and workplace leaders
Figure 2: A schematic representation of the approach to work ability impairments due to long COVID, their systematic evaluation and rehabilitation.
Offering social support and information is crucial to limit the impact of long COVID on workers. National and international sources of valid information exist on what long COVID is[11], how it can manifest and how it can be dealt with. Fostering awareness of and understanding for the problem is essential and will help facilitate further actions.
Assessing work ability impairment related to long COVID
Any long COVID symptom can be a source of significant discomfort and disability. Cognitive and physical symptoms can directly impact a person’s ability to work and present a significant risk for their occupational health and safety. It is therefore critical to ensure that those who suffer from long COVID are promptly identified and offered appropriate information and access to rehabilitation. A scheme for the systematic evaluation and rehabilitation of long COVID patients is presented in Figure 2.
There are several instruments to measure work ability and impairment caused by long COVID symptoms. The Work Ability Index (WAI) is an instrument used in clinical occupational health and research to assess work ability during health examinations and workplace surveys. The index is determined on the basis of the answers to a series of questions which take into consideration the demands of work, the worker's health status and resources. The worker completes the questionnaire before the interview with an occupational health professional who rates the responses according to the instructions. The WAI is a summary measure of seven items: current work ability compared with the lifetime best, work ability in relation to the demands of the job, number of current diseases diagnosed by a physician, estimated work impairment due to diseases, sick leave during the past year (12 months), own prognosis of work ability 2 years from now, mental resources.
The Duke Activity Status Index is an assessment tool used to evaluate the functional capacity of patients with cardiovascular disease, such as coronary artery disease, myocardial infarction, and heart failure. It is a 12-item questionnaire that assesses daily activities such as personal care, ambulation, household tasks, sexual function and recreation with respective metabolic costs. Each item has a specific weight based on the metabolic cost (MET).
The World Health Organization (WHO) suggests that any health facility in member states fills in and completes a long COVID case report form (CRF).[12] The form covers a wide range of possible complaints, both symptoms and medical conditions.An essential step in identifying long COVID is formalising patient complaints into measurable variables. For instance, a patient that complains of brain fog or poor concentration should undergo cognitive testing by an appropriate scale such as the Montreal Cognitive Assessment (MoCA). This will allow the physician to estimate the specific type of complaint (e.g. affecting memory or attention) and quantify its impact (for instance via the MoCA score). Furthermore, should the patient receive rehabilitation for that complaint, then the scale could be used to monitor improvement, and inform further decision making for the rehabilitation team.
Table 1provides a non-exhaustive list of scales that could be used for assessing different types of complaints and quantifying the effect.
Table 1. Examples of scales assessing specific symptoms relevant to long COVID and when to consider them.
Scale
When to consider it?
Work Ability Index (WAI) (Ilmarinen et al., 2007[13])
A worker’s ability to perform is compromised by long COVID
Duke Activity Status Index (DASI) (Hlatky et al., 1989[14])
Long COVID symptoms affect physical condition
Montreal Cognitive Assessment (MoCA)(Nasreddine et al., 2005[15])
Long COVID symptoms affect cognition
Visual Analogue Scale to Evaluate Fatigue Severity (VAS-F)(Lee et al., 1991[16]); Fatigue Severity Scale(FSS)(Krupp et al., 1989[17])
Workers experiencing excessive fatigue
Visual Analogue Scale Pain (Delgado et al., 2018[18])
Workers experiencing acute and chronic pain associated with long COVID
The Orthostatic Discriminant and Severity Scale (ODSS) (Baker et al., 2019[19])
Workers that have orthostatic intolerance and experience discomfort and are consequently unable to stand for prolonged periods of time
DePaul Symptom Questionnaire – 2 (DSQ-2) (Bedree et al., 2019[20])
Worker experiences worsening of long COVID symptoms after exertion
Hamilton Rating Scale for Anxiety (HAM-A) (Thompson, 2015[24])
Long COVID symptoms include anxiety
Hamilton Rating Scale for Depression(Hamilton, 1960[25])
6-Item Hamilton Depression Rating Scale (HAM-D6). (Bech et al. 1975[26])
Long COVID symptoms include depression
Rehabilitation approaches to long COVID
Long COVID is a complex condition, and rehabilitation approaches should be tailored to each individual patient. They can be either self-administered (i.e. self-rehabilitation), performed by a multi-professional team at a specialised centre, or at home via telemedicine approaches. For all, the goal is the holistic restoration of a patient’s health and of the ability to perform social activities and to resume social participation. However, some symptoms such as loss of smell and taste, fatigue, lack of concentration, loss of hair, or skin diseases might be particularly difficult to manage for some general practitioners, who are normally at the frontline of first identifying long COVID, especially in those patients that have not been hospitalised, indicating that treatment options for these symptoms may be limited or symptoms difficult to define.[27]
Self-rehabilitation
Self-rehabilitation involves methods and techniques that workers suffering from long COVID can use as part of their daily routine. WHO has provided guidance for self-rehabilitation,[28]by recommending several self-administered interventions that can help mitigate the effects on physical and mental health. Advice covers exercises to improve breathlessness, strengthening physical fitness, managing voice problems and managing problems with attention, memory and thinking, to improve physical fitness, breathlessness, strength, balance, coordination and energy levels, as well as mood and cognition. A synopsis is provided in Table 2.
Table 2. Summary guidance on self-rehabilitation for COVID-19
Long COVID complaint
Suggestions for self-rehabilitation
Managing breathlessness
Breathlessness is a common problem for people hospitalised due to COVID-19. WHO’s guide suggests several body positions that may help breathlessness such as:
High side lying.
Forward lean sitting.
Standing with back support.
Alternatively, breathing techniques may also help with breathlessness. Two examples of these techniques are:
Controlled breathing, which focuses on relaxing and becoming aware of one’s breathing;
Paced breathing, where during a strenuous activity, such as e.g., climbing a flight of stairs, one inhales in before climbing up a step, and exhales while making the effort to climb that step.
For both techniques, breathing in is best done through the nose and breathing out through the mouth.
Exercising after leaving the hospital
Exercise is expected to improve physical fitness, breathlessness, strength, balance, coordination and energy levels, as well as mood and cognition.
WHO’s guidance focuses on exercising both comfortably and safely, with examples for the following:
Warmup exercises, which prepare one’s body for further exercise routines; they should typically last at least 5 minutes.
Fitness building exercises, which should be ideally performed for 20-30 minutes, 5 days a week. WHO’s guidance provides examples for several of those exercises, but it furthermore states that any activity that makes one breathless (specifically, within the setting of exercise) should be counted as a fitness building exercise. Breathing in as one begins the exercise, and breathing out as one performs it is also suggested. Upon feeling breathless, one can utilise the positions previously suggested for the management of breathlessness.
Strength building exercises, aiming for three sessions of strengthening exercise per week. Contrary to fitness building exercises, successfully performing a strength building routine should not make one feel breathless; instead, involved muscles should feel tired, as if having worked hard.
Cool down exercises, which aim to return one’s body to normal before stopping exercise altogether. Cool down exercises should last approximately 5 minutes, and upon stopping, one should not feel breathless.
Managing problems with one’s voice
Straining one’s voice should be avoided; instead, talking only when it’s comfortable;
Taking rests and trying not to speak continuously;
Try humming;
Using alternative ways of communicating, such as writing notes.
Managing eating, drinking, swallowing
Problems with eating, drinking and swallowing are more frequent in people that had been intubated.
It is important to be especially careful when swallowing, and preferably to concentrate.
While eating, sitting and remaining upright is important.
Eating smaller meals throughout the day instead of full meals is advisable.
Coughing, choking or impaired breathing while eating should prompt a break.
Managing problems with attention, memory, and thinking clearly
Physical exercise can also help with brain health. It is important to introduce exercise gently into the daily routine, focusing on both strength and fitness building exercises.
Brain exercises refer to any challenging activity that requires active mental effort. These can be games, quizzes, puzzles etc. It is again important to start with activities that can be completed successfully before moving on to more demanding ones.
Self-prompting by creating lists, setting up alarms or calendars can help with maintaining and managing one’s routine.
Breaking down activities into easier and/or smaller steps can help mitigate the impact of cognitive problems on one’s life.
Managing activities of daily living
Adjusting expectations is an important first step, as it may not be easy to manage things as before, and energy levels, both physical and mental, are less than what they were.
Energy conservation and pacing; performing tasks or daily activities from a comfortable position (e.g. sitting down rather than standing) and resting between tasks.
Easing back into the daily routine prior to COVID-19 or long COVID adjusting current energy levels and gradually increasing them.
Accepting help from others with activities that have become difficult to manage.
Managing stress and problems with mood
Taking care of one’s basic needs is important for managing stress and mood problems. Getting enough quality sleep, eating healthily and remaining physically active are important steps towards achieving this goal.
Self-care is also important. Staying socially connected and doing relaxing activities are effective ways of managing stress.
When to seek medical advice
Unsupervised rehabilitation may be effective, but the symptoms that are addressed may reflect a serious underlying condition. WHO’s guidance mentions several circumstances under which long COVID patients should seek medical advice, for instance when:
Breathlessness becomes more taxing or does not improve, despite simple attempts to alleviate it;
Breathlessness occurs with minimal activity and it is not readily alleviated, e.g. with the help of body positioning;
Exercise brings about new symptoms such as nausea, chest pain or tightness, dizziness, intense sweatiness, shortness of breath;
Mental faculties do not improve or even deteriorate, making daily life difficult, including resuming work;
Eating and drinking remains difficult and does not improve after adopting accommodations suggested in Table 2;
Mood disorders worsen, including anxiety or depression.
Rehabilitation from physical complaints linked to long COVID
The following sections describe each of the most reported physical complaints linked to long COVID. The structure they are presented in is:
The symptom explained: a description of the symptom.
How can it be measured: indicative scales that can be used to describe the symptom. Information on the available scales/instruments is provided in Table 1.
What the worker needs to know: information that workers experiencing the symptom may find useful.
Self-rehabilitation: options and methods for self-management of the symptom.
Workplace adaptations: ways by which the symptom can affect work ability.
Generally, the patient’s progress and the effectiveness of rehabilitation should be continuously reviewed.Baseline performance here refers to the performance achieved by each worker when a rehabilitation program starts. This will later help establish the trajectory of that performance as rehabilitation continues and determine whether the measures implemented objectively improve the patient’s condition. Specialists will focus on getting a simple measure of physical fitness, such as the 6-minute walk distance test or the 30 seconds sit to stand test. The six minute walking test (6MWT) was developed by the American Thoracic Society and it was officially introduced in 2002, coming along with a comprehensive guideline. The distance covered over a time of 6 minutes is used as the outcome by which to compare changes in performance capacity. This test measures the distance that a patient can quickly walk on a flat, hard surface in a period of 6 minutes. The 30 Second Sit to Stand Test is also known as 30 second chair stand test (30CST), is for testing leg strength and endurance in adults. The 30-second chair stand involves recording the number of stands a person can complete in 30 seconds. The results of these tests will help set the goals for future rehabilitation.
Fatigue
The symptom explained: Fatigue in the setting of long COVID refers to exhaustion, lack of energy and physical activity intolerance. This loss of energy is not proportional to physical activities attempted and is not restored by rest or sleep. Fatigue may exist on its own or reflect underlying cardiopulmonary disease.
How can it be measured: Fatigue Severity Scale. The Visual Analogue Scale to evaluate fatigue (VAS-F) consists of 18 items relating to the subjective experience of fatigue. Each item asks respondents to place an “X,” representing how they currently feel, along a visual analogue line that extends between two extremes (e.g., from “not at all tired” to “extremely tired”). The Fatigue Severity Scale (FSS) is a self-reported measure designed to capture the impact of fatigue on a person’s daily functioning and quality of life. A set of predefined statements are answered by a Likert-scale ranging from “strongly agree” to “strongly disagree”.
What the worker needs to know: Fatigue is a frequently reported symptom of long COVID, when work-associated tasks they were previously capable of performing have become more taxing and strenuous.
Self-rehabilitation: Symptom-adjusted physical activity, meaning physical activity that is adjusted to the severity of fatigue experienced. Exercise can be modified to be more relaxed or more intense (easier or more intensive workout, for instance), depending on how well one tolerates each level of exercise. Education by a rehabilitation specialist and individualised training regimens can be provided and followed by patients at home.
Specialist rehabilitation Exercise should be carried out 3 times per week, with a duration of 30-50 minutes, on 70% of heart rate reserve. However, there should be a regular reassessment. Fatigue that does not improve even after rehabilitation should prompt medical re-evaluation. Fatigue that worsens with rehabilitation should be reviewed by the rehabilitation team and exercises training modified.
Workplace adaptations: Fatigue is not only disabling as regards physical activity, but impairs overall quality of life and work ability simultaneously. Phased return to work, workload review and workplace modifications should be considered.
Post-exertional symptom exacerbation
The symptom explained: Post-exertional symptom exacerbation (PESE) or post-exertional malaise (PEM), is defined as the worsening of long COVID symptoms, typically 12 to 72 hours after performing mental or physical activities that were previously tolerated.
How can it be measured: DePaul Symptom Questionnaire – 2 (DSQ-2). The DePaul Symptom Questionnaire 2 (DSQ-2) records the frequency and severity of myalgic encephalitis and chronic fatigue symptoms (CFS) over the past six months. Post-exertional malaise is captured in the setting of the Fukuda CFS diagnostic criteria, and DSQ-2 provides extra items to describe it, such as “muscle fatigue after mild physical activity; worsening of symptoms after mild physical activity; and worsening of symptoms after mild mental activity.”
What the worker needs to know: Post-exertional malaise leads to symptom worsening that lasts for days or weeks and may be responsible for long COVID symptom relapse and / or fluctuation. Practically, this means that the more you attempt to do, the worse you get.
Self-rehabilitation: The main consideration is for the worker to determine their “energy envelope” or energy limits for physical activity and adjust their daily routine. They should plan activity and rest to stay within these limits; this is called staying within the “energy envelope”. Limitations may be different for each person affected by long COVID. Keeping individual activity and symptom diaries may help them identify their personal limitations.[29]
Specialist rehabilitation: The first consideration should be to do no harm. Intense activity, especially aerobic, may harm the worker due to intolerance of patients experiencing post-exertional malaise. Rehabilitation specialists should balance exercise against inactivity, which will lead to symptoms and disability setting in. Activities could be swimming, pilates, yoga, functional training or flexibility and mobility training.
Workplace adaptations: Increased physical burden, especially work-related, will only serve to prolong and establish post-exertional malaise. A phased return to work plan, with self-adjustable burden should be implemented.
Orthostatic intolerance
The symptom explained: Orthostatic intolerance refers to blood pressure and heart rate instability when standing upright. Other related symptoms may be temperature dysregulation, excessive sweating, lightheadedness, chest pain and loss of consciousness, gastrointestinal dysfunction and heat intolerance. Orthostatic intolerance may occur within the setting of an autonomous nervous system dysfunction caused by COVID-19.
How can it be measured: The Orthostatic Discriminant and Severity Scale (ODSS). The Orthostatic Discriminant and Severity Scale (ODSS) scale was developed to discriminate the origin of common, non-specific symptoms such as dizziness, light-headedness and fatigue as either related to orthostatic intolerance or not.
What the worker needs to know: Standing upright from a sitting or prone position, especially for prolonged periods of time, may be especially harmful, as orthostatic intolerance may result in dizziness or even loss of consciousness.
Self-rehabilitation: Exercise training, increasing salt uptake in foods and getting up slowly from a sitting or lying position are among the easiest to implement measures to deal with orthostatic intolerance.[30] For orthostatic intolerance that manifests as low pressure after standing up (known as orthostatic hypotension), additional measures can be effective:
Hydration: during days when orthostatic hypotension is worse, the worker should drink plenty of water. Concerned workers should therefore have easy access to drinking water.
Tailored physical exercise and improving fitness will improve symptoms; inactivity, to the contrary, will only worsen it.
Sleeping with the head of the bed slightly elevated.
Contracting the muscles below the waist for about half a minute at a time will raise blood pressure when the symptoms set in.
Specialist rehabilitation: Rehabilitation specialists should determine whether the cause is long COVID or another related condition, e.g., undiagnosed diabetes. Orthostatic intolerance may not only involve blood pressure and should prompt further medical investigations for other undiagnosed (e.g. cardiovascular) comorbidities. They should help the worker determine a safe exercise program, generally gentle at first. The rehabilitation team should also determine fluid and salt intake and readjust according to symptoms and the worker’s response.Workers with post-exercise malaise may require modification of exercise regimens for long COVID patients.
Workplace adaptations: Orthostatic intolerance may require workplace modification to prevent severe occupational safety and health (OSH) risks. Workers working at heights and on uneven surfaces may be at an increased danger of falling. Workload and task modification to minimise time standing, breaks between long periods of standing and the possibility to telework should also be considered.
Breathing impairment
Definition: Breathing impairment or dyspnoea refers to a subjective feeling of inadequate breathing that causes distress.
How can it be measured: The Modified Borg Dyspnoea Scale is a self-reported measure of breathlessness. The patient is asked to rate the severity of the difficulty they have in breathing and is rated from 0 (none) to 10 (maximal).
What the worker needs to know: Long COVID patients can experience dyspnoea in various settings (e.g., while resting, upon physical exertion). It may be constant, or fluctuating, and may be accentuated by mood disorders, especially anxiety.
Self-rehabilitation: Self rehabilitation for breathing impairment focuses on both physical and mental aspects, training the patient on management techniques, such as those in Table 2:
Modifying lying and sitting positions;
Breathing exercises, such as controlled and paced breathing;
Nasal breathing;
Physical exercise, when post-exercise symptom exacerbation is absent;
Psychological support, when anxiety or depression also contributes;
Specialist rehabilitation: A clinical exercise physiologist should be supervising and creating a rehabilitation programme to reduce the symptoms. Primary care, respiratory medicine and occupational physicians should be aware that although subjective, dyspnoea can reflect an evolving medical condition. Dyspnoea that does not improve or worsen with rehabilitation should be re-evaluated.
Workplace adaptations: As breathlessness may not be continuous, or enhanced by stress and anxiety, workload modification and psychological support should be made available to workers. Work that requires the use of respiratory protection should be avoided.
Arthralgia
The symptom explained: Arthralgia refers to inflammatory joint pain. In long COVID patients, this pain may be of any quality, onset and duration. Reactive arthritis usually involves inflammation of the joints (arthritis) and tendons, which can cause joint pain, tenderness and swelling – usually in weight-bearing joints such as your knees, feet and ankles; lower back and buttock pain; swelling of fingers and toes; joint stiffness – particularly in the morning. It is usually linked to infections. People with polyarthralgia have pain in multiple joints. Symptoms may include pain, tenderness, or tingling in the joints and reduced range of motion. Polyarthralgia is similar to polyarthritis, but it doesn't cause inflammation.
How can it be measured: The visual analogue scale (VAS) is a pain rating scale first used by Hayes and Patterson in 1921. Scores are based on self-reported measures of symptoms that are recorded with a single handwritten mark placed at one point along the length of a 10-cm line that represents a continuum between the two ends of the scale - “no pain” on the left end (0 cm) of the scale and the “worst pain” on the right end of the scale (10 cm). The values can be used to track pain progression for a patient or to compare pain between patients with similar conditions. In addition to pain, the scale has also been used to evaluate mood, appetite, asthma, dyspepsia, and ambulation.
What the worker needs to know: Arthralgia as a symptom needs prompt evaluation by a medical specialist, as it may related to an evolving medical condition. Care must be taken to not strain a painful joint; “pushing through” despite the pain, especially if it´s increasing, will result in harm and potentially lasting consequences.
Self-rehabilitation: Pain and self-management strategies for chronic pain may be effective, as well as tailored exercise training, in the absence of post-exercise malaise and adapted to symptom severity. Pain that increases with exercise should prompt the worker to stop.
Specialist rehabilitation: Identifying the cause behind joint pain is a primary concern and may supersede rehabilitation. Arthralgia in a setting of long COVID may be associated with reactive arthritis and polyarthralgia.Prescription of anti-inflammatory medication may be required, as well as further investigations. The role of specialist rehabilitation here, even with minimally supervised exercises (swimming, yoga, stretching, exercising 3 times per week (30-50 minutes sessions on 60% of maximal oxygen uptake)) is to determine safe exercise regimes tailored to the needs of the patient. Physical exercise training and aquatic exercises may be effective in improving joint pain, physical function, and quality of life. However, according to the WHO’s living guideline[31], evidence on the effectiveness of specific interventions in the post-COVID setting is not available.
Workplace adaptations: Pain and the potential involvement of joint inflammation represent important limiters of physical activity. Demanding physical work should be avoided until pain is manageable and post-exercise malaise is excluded.
Other physical symptoms
Long COVID may manifest in a multitude of other symptoms, in any combination and severity, for instance:
Problems with the sense of smell
Problems with olfaction (i.e., the sense of smell) are frequent in those with a history of COVID-19. Rehabilitation should be attempted via a process called olfactory training. This includes retraining the patient in identifying smells, by presenting specific odours via essential oils in screw-cap jars. Other odorants may also be used, although evidence on the effectiveness of this intervention is lacking. There are indications that such symptoms are a challenge for rehabilitation, although they may be very relevant to some professions such as cooks.
Voice impairment
Voice impairment typically affects those workers that had more severe disease and required admission to the intensive care unit (ICU). Voice rest, non-verbal communication methods (e.g., writing down something that would take too long to explain) and other exercises may be effective. In addition, any combination of respiratory exercises and vocal training may be considered. Currently, not enough is known about voice impairment linked to COVID-19 infections to determine which approach is expected to have better results.
Voice impairment may particularly affect workers in professions where speaking is required, such as in education or call centres. General guidance on voice management exists, but more targeted strategies are needed to support workers in these professions.
Swallowing impairment (dysphagia)
As with voice impairment, swallowing impairment occurs typically in those with more severe Covid-19 disease or ICU admission and after intubation[32]. Swallowing impairment is a potentially serious condition, as it may lead to aspiration pneumonia, drawing food into the respiratory system rather than the oesophagus, resulting in infection. In rehabilitation, a combination of education and skills training on head and body positioning, manoeuvres, and dietary modifications, such as modifying food composition depending on whether swallowing is more difficult with solids or liquids, as well as swallowing exercises are recommended. Cognitive impairment, when severe, can also contribute to swallowing impairment and should be screened for. Workers who are affected may have to change their eating habits and have several meals a day. Reorganisation of work and the possibility to have smaller meals at a quiet and calm location may be helpful for these workers.
Sleep disturbances
Sleep disturbances linked to long COVID occur on their own, or due to another symptom, for example:
Difficulty breathing that worsens at night;
Anxiety and depression resulting in insomnia and awakenings;
Arthralgia that does not improve, with the pain keeping the worker awake.
Sleep disruption in anxiety disorders may manifest as difficulty falling asleep, early or sequential awakenings during a night’s sleep, lessened total sleep time or non-restorative sleep.
Sleep disturbances can drain a worker of their energy, both mental and physical. This means that they become not only less productive, but also vulnerable to OSH risks. Daytime sleepiness because of sleep disturbances can put workers at serious risk in certain professions, such as professional drivers and construction workers.
Proposed Interventions
In the healthcare setting
An assessment of sleepiness and the potential development of sleep disordered breathing should be incorporated into standard practice for the evaluation of long COVID. Established measures such as the Epworth Sleepiness Scale (ESS) and the Berlin Questionnaire can be used by both occupational or primary care physicians. The ESS is a self-administered questionnaire with 8 questions. Respondents are asked to rate, on a 4-point scale (0-3), their usual chances of dozing off or falling asleep while engaged in eight different activities. The higher the ESS score, the higher that person’s average sleep propensity in daily life, or their ‘daytime sleepiness’. It is also used to diagnose obstructive sleep apnoea.[33]The Berlin Questionnaire serves to estimate the likelihood of obstructive sleep apnoea, the most prevalent sleep disorder. Alternatively, referral to another related specialty (long COVID centre, sleep clinic, respiratory medicine clinic) may help. Depression or anxiety should always be considered as possible causes for disrupted sleep, if other physical complaints are absent.
An initial and follow-up evaluations of sleepiness and sleep disturbances should be done, to determine whether they have resolved.
In the workplace and daily life
Workers should be able to discuss sleep-related problems with the occupational physician. Training and awareness on the wide variety of possible symptoms, such as sleepiness or a sense of non-restorative sleep may further help. Sleep hygiene advice[34], and stress management are simple and effective measures. Being physically active during the day and exercising will help with sleep coming naturally at night. Psychological interventions such as cognitive behavioural therapy may also be reasonably effective when other measures are not effective.
Workplace adjustments, including adjustable workload and working hours should be offered by employers. Shift work should also be reviewed by line managers, OSH professionals and human resources departments along with affected workers and their representatives; for example, changing from alternating (morning-night) shifts to stable, daily working hours (e.g., 9.00 am to 05.00 pm) may be preferable and support the worker in the attempt to regain their sleep routines.
Cognitive rehabilitation
Cognition refers to the mental processes that represent our means of understanding and interacting with the world. Long COVID affects cognition in many ways, for instance impairing memory and concentration so that affected workers are unable or less capable to perform complex tasks or demanding mental tasks. Long COVID patients have described these symptoms as “brain fog”[35]. Among long COVID patients, women, those who suffered respiratory problems at COVID-19 onset and those admitted at an ICU during their COVID-19 infection were most affected.
Cognitive impairment can affect rehabilitation itself, as the worker may not be able to effectively participate in the program. Poor thinking, decision making, and memory affect people with work that relies on complex data more.Cognitive complaints can affect manual workers too, however, and put their safety and health at risk in the workplace. Older workers, who may be susceptible to age-related cognitive complaints, may experience this worse than younger ones. Equally, women and those that experienced severe COVID-19 resulting in ICU admission may be more vulnerable.Poor sleep and fatigue can also make cognitive problems worse.
There is a stigma associated with disorders of cognition, but only if awareness of what they are, where they come from and how can they be dealt with has not been addressed. Awareness needs to be raised among employers, OSH experts and coworkers about cognitive disorders linked to long COVID and how they can limit the workers who are affected, but also the fact that rehabilitation is possible. Table 3 provides an overview of complaints that are associated with a specific area of cognition.
Table 3. Examples of symptoms and complaints that can be associated with a specific area of cognition affected.
Area of cognition
Symptoms and complaints
Attention
Difficulty focusing on a particular subject or trail of thought
Difficulty following conversations
Difficulty performing mental calculations
Becoming easily distracted
Processing Speed
Difficulty participating in conversations
Difficulty adapting to new information
Difficulty adapting and learning new skills
Executive Function
Increased frequency of errors during the performance of work- or daily routine- related tasks
Difficulty planning ahead and organising daily or job-related routines (finance, home choirs, organising workload)
Difficulty switching between two tasks performed at the same time / multitasking
Language
Struggling to find the correct word to describe an object
Less embellished language, poor grammar, syntax and fluency
Difficulty in understanding the meaning of words
Difficulty repeating words
Difficulty participating in conversations due to all of the above
Difficulty with written language, expressing one's thoughts and accurately describing a situation
Motor Control
Slow and imprecise movements
Diminished capacity to operate machinery, drive a vehicle
Difficulty performing activities that require complex movements, e.g. dancing
Visuospatial and visuoconstruction skills
Difficulty driving
Impaired depth perception
Difficulty recognising faces and their characteristics
Difficulty identifying objects
Impaired orientation, especially in newly visited places
Mental Fatigue
Diminished capacity to perform mental tasks
Memory
Difficulty learning and recalling new information
Difficulty recalling old information, such as memories
Difficulty keeping appointments
Cognitive rehabilitation refers to neuropsychological approaches aiming to restore cognitive function following acquired damage to the central nervous system.[36] Guidelines on the diagnosis and interventions on cognitive impairment in the setting of long COVID[37]have been developed by the American Academy of Physical Medicine and Rehabilitation (AAPM&R) Multi-Disciplinary PASC Collaborative (PASC Collaborative), including the following considerations:
Screening positive for a cognitive symptom should prompt further evaluation by a specialist (e.g., neuropsychologist, occupational or speech therapist, etc). Medical conditions that may reinforce cognitive impairment, such as pain, sleep and mood disorders should also be treated appropriately. Furthermore, medication that could affect cognition directly or indirectly should be reviewed by treating physicians and potentially reduced or deprescribed.
Specific approaches to cognitive rehabilitation
Cognitive rehabilitation approaches are designed to address complaints that affect specific cognitive domains such as e.g. memory[38]or language[39]. Translating symptoms (e.g. “I keep forgetting where I’ve put my keys”) into cognitive domains (e.g. attention) is a first step to identify the magnitude and specifics of cognitive impairment. An overall assessment of cognitive performance can be made using psychometric testing via e.g. the Mini-Mental State Examination (MMSE) or the Montreal Cognitive Assessment (MoCA). The Montreal Cognitive Assessment (MoCA) was designed as a rapid screening instrument for mild cognitive dysfunction. It assesses different cognitive domains: attention and concentration, executive functions, memory, language, visuoconstructional skills, conceptual thinking, calculations, and orientation. This assessment should be done under the guidance of a qualified rehabilitation specialist (for example a primary care physician in their office or a neuropsychologist in a rehabilitation centre).
Aside from affecting specific cognitive domains, long COVID may result in increased mental fatigue, meaning diminished capacity for mental exertion, added to fatigue associated with performing physical tasks.[40]
The backbone of cognitive rehabilitation is identifying how one’s mental abilities have been affected. Based on this estimation, tailored approaches can be implemented by cognitive rehabilitation specialists, typically psychologists and neurologists. Table 4 provides an overview of techniques that can be applied:
Table 4. Examples of interventions and rehabilitation strategies per cognitive domain
Cognitive domain
Intervention and rehabilitation strategy examples
Attention
Attention process training: focuses on improving attention to desired tasks while ignoring irrelevant information.
Metacognitive strategy training: This type of rehabilitation approach consists of several steps. An example of what can be expected from metacognitive strategy training is the following[41]:
The patient becomes aware of their own cognitive impairment. This includes self-evaluation and self-regulation.
Subsequently, the patient develops plans and adapts to their impairment.
By performing the previous steps, the patient improves their ability to perform tasks affected by their impairment.
Timed structured activities: timed activities help patients adjust to time management while performing rehabilitation tasks in sequence.
Processing Speed
Accommodating adjustments, such as reviewing information at one’s own pace; repeated practice of skill; breaking down complex components and then reassembling them.
Cognitive mobile games: Reviewed in[42] these may enhance processing speed and can be used with any smartphone or tablet.
Executive Function
Metacognitive strategies that focus on increasing self-awareness.
Use of organisational aids, e.g., digital calendars.
Language
Semantic feature analysis[43] using charts that help patients associate pictures with words.
Errorless learning: This rehabilitation approach relies on preventing errors during the rehabilitation process. Errorless learning can be utilised in both disorders of language and memory; an example of its application is the following:[44]
The patient is shown a picture of an object.
The correct word for the depicted object is provided to the patient, to prevent incorrect recall.
Supported conversation relies on training a discussion partner (spouse, coworker, nurse, caretaker or other) on supportive communication with people with language impairments.[45]
Motor Control
Motor control and motor rehabilitation are often incorporated in exercise training and other physical rehabilitation or mind-body approaches. They emphasise re-training the control of finer movements, coordination and balance.
Visuospatial - visuoconstruction skills
Use of visual cancellation tasks e.g. the patient is asked to cross out (or cancel) a specific symbol when it appears on a computer screen. The patient is also taught strategies for visual organisation such as scanning from left to right, top to bottom for symbols, shapes, numbers, and other similar tasks.
Mental Fatigue
Energy Envelope Theory: This theory and related approaches rely on the concept of “energy envelope”, i.e. one’s maximum available energy to accomplish tasks; interventions based on this theory suggest the determination of a patient’s physical and mental limits and performing tasks well within them.
Mindfulness-Based Stress Reduction (MBSR): This approach combines physical exercises (e.g. yoga) and mental techniques (e.g. meditation) to reduce stress.
Memory
Errorless learning.
Spaced retrieval strategies: This strategy relies on remembering information presented at incremental intervals of time. Recall mistakes are corrected immediately, and when they occur, the retrieval interval reverts to immediately previous one. Resuming the recall process after an error occurs is also followed by a corresponding increase at sequential intervals between information to be recalled.
Proposed Interventions
In the healthcare setting
An assessment of cognitive function, depression and anxiety should be incorporated into the assessments typically performed when evaluating workers for long COVID. Persistent cognitive impairment even in the setting of long COVID may reflect an underlying condition that, if promptly recognised, may be treatable (e.g., vitamin deficiency, metabolic disease, sleep disorder, etc).
Awareness and education on what cognitive impairment is and how it affects one’s life is the first and perhaps most important step. The Post-COVID-19 Functional Status scale[46]is a screening tool that can help physicians get a broad estimate of the potential underlying long COVID syndrome, and identify cognitive complaints, depression and anxiety.
An occupational physician can use simple cognitive screening tests to determine whether cognitive complaints can be objectively captured. However, if a worker experiences cognitive complaints but does not score low in an appropriate scale, it is always better to refer the worker to a specialist.
Cognitive rehabilitation is feasible, and examples of successful return-to-work abundant in the literature. Rehabilitation should be targeted at those complaints that affect the worker. Most cognitive rehabilitation techniques can be administered by a trained professional, typically at long COVID centres or specialised services. Rehabilitation should focus not only on strengthening affected cognitive domains, but also on helping the patient to develop mechanisms to cope with ongoing disability. Cognitive and physical rehabilitation should be combined where possible, as both can help a worker to return to work and experience improved quality of life.
Cognitive impairment due to long COVID may be persistent, and is often complicated by mood disorders, anxiety and depression. Regular (i.e. every six months) evaluations may therefore be reasonable. Impairments that do not improve should prompt medical re-evaluation in a specialised service.
In the workplace and daily life
Cognitive and emotional complaints in the workplace and daily life are often underreported due to social bias and stigma especially in younger workers. COVID-19 survivors with impaired mental health may experience both job insecurity and financial instability and exposure to job insecurity for middle aged adults in the US and England has been correlated with subsequent cognitive impairment[47].
Employers should work together with human resource managers, line managers, supervisors, OSH preventive services and occupational physicians to establish an open communication policy about mental health complaints and ensure that workers who are affected and their co-workers are informed on what constitutes cognitive or affective long COVID symptoms.
Adjustable work hours, adjustable workload and phased return to work may facilitate return to work, especially regarding demanding mental tasks that they may need time to readjust to.
Employers should also consider utilising government or social security provisions, COVID-19 specific or otherwise, that will keep workers employed.
For those returning to work, frequent assessments of work ability and primary symptoms should be carried out, to ensure workload is tolerable and does not trigger the return of symptoms. Returning to one’s previous routine, including resuming work and other physical or mental activities may in some cases cause long COVID symptoms to re-emerge. Re-evaluating those returning may help prevent such a deterioration. Regular exercise could improve both cognitive symptoms and potential sleep hygiene issues.
As with other symptoms, workers suffering from long COVID should be actively encouraged to express their concerns as well as perceived cognitive changes, this has been shown to be successful in other diseases complicated with cognitive complaints, where cognitive training was also shown to ameliorate cognitive decline. Cognitive behavioural therapy and appropriate referral to neurological and psychological services can also be beneficial.
Mental health issues in long COVID
Mental health issues may arise as part of long COVID. A positive workplace culture where awareness and empathy for mental health issues is high can help workers in need.
Table 5 provides an overview of symptoms, in particular for depression and anxiety. To safely diagnose and manage them, a mental health professional has to be involved early on.
Table 5: Symptoms that are indicative of mental health issues
Depressive symptoms
Anxiety symptoms
Persistent low mood and sadness,
Markedly diminished participation in formerly pleasurable activities
Sleep disturbances,
Changes in cognition
Changes in appetite
Mental and physical fatigue
Altered, negative perception of oneself, abilities and self-worth
Thoughts of self-harm or even suicide
Restlessness, uncontrollable, invasive or “racing” thoughts.
Reduced attention / difficulty concentrating.
Feelings of dread
Sleep disruption
Changes in appetite
Irritability / confrontational attitudes
There are several psychometric instruments to measure anxiety and depression. The Hamilton Rating Scale for Anxiety (HAM-A) was one of the first rating scales developed to measure the severity of anxiety symptoms and is still widely used today in both clinical and research settings. The scale consists of 14 items, each defined by a series of symptoms, and measures both psychic anxiety (mental agitation and psychological distress) and somatic anxiety (physical complaints related to anxiety). The Hamilton Rating Scale for Depression (HRSD), also called the Hamilton Depression Rating Scale (HDRS), sometimes also abbreviated as HAM-D, is a multiple-item questionnaire used to provide an indication of depression, and as a guide to evaluate recovery. Originally published in 1960, it was revised in 1966, 1967, 1969, and 1980. The questionnaire is designed for adults and is used to rate the severity of their depression by probing mood, feelings of guilt, suicide ideation, insomnia, agitation or retardation, anxiety, weight loss, and somatic symptoms. The HAM-D6 covers the following core depressive symptoms: depressed mood (item 1), feelings of guilt (item 2), loss of interest (item 7), psychomotor retardation (item 8), psychic anxiety (item 10), and general somatic symptoms (item 13).
For the clinical rehabilitation management of anxiety and depression in workers with long COVID, the implementation of a mind-body approach is recommended, combining psychological support with exercise training. Mindfulness-based approaches and support groups may also be useful to reduce distress in workers.
Mental health issues and the workplace
It is important to consider the workplace outside the impact of long COVID and its impact on mental health. Even without accounting for the pandemic and long COVID, 15% of working-age adults were estimated to have a mental disorder in 2019.[48] Globally, 12 billion working days are lost every year to depression and anxiety, at a cost estimated to 1 trillion US dollars per year due to lost productivity. The problem is only made worse by the added effects of long COVID. Poor working conditions may pose a risk to mental health: discrimination, inequality, excessive workloads, job insecurity and low job control are contributing factors.
According to WHO guidance[49],, there are effective actions that may prevent mental health issues at work, while supporting affected workers. These actions are:
Manager training for mental health:By attending such training, managers learn to recognise emotional distress in their workers. Furthermore, it allows them to develop skills such as open communication and active listening. Managers with this skillset can identify workplace-related stressors to mental health and actively contribute to remedy them.
Training for workers in mental health literacy and awareness: This action serves to improve knowledge on mental health conditions, their recognition, and the reduction of stigma.
Interventions for individuals, serving to train workers on stress management skills they can implement.
There are general measures and principles guiding the return-to-work plan for long COVID patients for those facing (specifically) mental problems.Work schedule adaptations such as flexible working hours, extra time to complete tasks, modified assignments to reduce stress, leaves of absence for health appointments are among measures considered effective in WHO’s guidance on mental health. Combining clinical care with vocational rehabilitation and phased return to work can also help workers deal with the burden of psychological distress.
Supported employment initiatives will help those facing the more severe spectrum of mental health problems to maintain their jobs and income, while being treated by mental health professionals.
Health equity and rehabilitation
Awareness and education should aim to make the workplace a positive space to return to, that is both safe and welcoming and provides opportunities for all workers affected by long COVID. There are several worker groups that may need particular attention:
Women of working age are disproportionally affected by long COVID[50],[51] . Their rehabilitation needs may conflict with their responsibilities beyond work, such as child or elderly care. This problem should be acknowledged and considered when determining an individual return-to-work plan, as well as when stakeholders (employer, manager, HR department) re-arrange workloads and schedules. Larger organisations and companies should consider offering or easing access to childcare services to enable women resume participation and attend rehabilitation.
Workers experiencing mental health issues due to long COVID may face discrimination, feel isolated, or perceive the workplace as a hostile environment. Awareness is key; both of how mental health issues can manifest, and on how people that experience them can be approached. WHO has suggested training managers into mental health issues; this may help immensely with identifying signs of such problems in those they directly supervise. Furthermore, it will help them take decisions in a manner that promotes a positive working environment and shields mental health. EU-OSHA has also published guidance for maintaining affected workers at work
Any long COVID manifestation can lead to significant disability and introduce OSH risks. For workers who have been particularly affected by long COVID, such as those with serious SARS-CoV2 infections and those who have been in intensive care, particular measures may be needed. OSH experts should consider individual risk assessments for affected workers; HR and line managers can also help with redesigning job-related tasks and routines to prevent scenarios that may exacerbate symptoms (e.g., prolonged standing, exposure to continuous heat, alternating shifts etc).
All actors in the workplace should collaborate and make sure that adequate time and space is given to rehabilitation. Workplaces and working conditions should be revised by OSH professionals, including adapted spaces for breaks, meals and self-rehabilitation. Job simplification, workload re-distribution, and other reasonable adjustments such as teleworking, may help those facing particular trouble returning to work. EU-OSHA has previously published a guide for managers[52] that provides guidance on general aspects of long COVID and the return to work. It provides advice for employers on how to organise return to work for workers, with particular care taken not to impose modifications, but to implement a participatory and adaptable approach in close collaboration with concerned workers and the occupational health service or physician.
Resources
Many national social security systems across Europe have set up plans to remediate long COVID and provide support that keeps those affected by it employed. Employers should seek information about how they can best use government-issued provisions. Guidelines may also be available at national level.[53],[54],[55]
EU-OSHA resources
EU-OSHA, European Agency for Safety and Health at Work, 2021a. COVID-19 infection and long COVID – guide for workers. https://osha.europa.eu/en/publications/covid-19-infection-and-long-covid-guide-workers.
EU-OSHA, European Agency for Safety and Health at Work, 2021b. COVID -19 infection and long COVID – guide for managers. https://osha.europa.eu/en/publications/covid-19-infection-and-long-covid-guide-managers
EU-OSHA, European Agency for Safety and Health at Work, 2022b. Long COVID: Challenges for prevention and measures to diminish the effects on OSH. OSH wiki article. https://oshwiki.osha.europa.eu/en/themes/long-covid-challenges-prevention-and-measures-diminish-effects-osh
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