It can take the body weeks to recuperate from a respiratory illness. During the tail end of recovery, even with the first instance of relief, you might be itching to get moving after being bedridden for so long. However, the available evidence regarding when it is ok to reintroduce your body to physical activity is unclear,¹ as people respond to illnesses differently, and course of action relies on lingering symptoms and the body’s overall condition.^1,2 

EVALUATE YOUR SYMPTOMS

Many healthcare experts encourage following the “above the neck” rule.¹ Basically, this rule recommends only engaging in pre-existing workout routines or physical activity of any intensity if symptoms of illness are only present above the neck (e.g.,  earache, slight nasal congestion, mild sore throat, sinus pressure). Exercising while experiencing below the neck symptoms, on the other hand, such as frequent coughing, productive (phlegmy) cough, fever, nausea, vomiting, and diarrhea, is not recommended and could results in complications.¹  

Dehydration, weakness, muscle aches, and loss of appetite typically accompany a fever. Exercising with a fever can worsen its intensity, amplifying the above symptoms and increasing the risk of injury due to a fever-related decrease in muscle strength and impaired coordination.^1,2 The same goes for nausea, vomiting, and/or diarrhea, which already put the body at risk for dehydration and weakness. Frequent and/or productive coughing can hinder the ability to breathe deeply, especially when the heart rate is increased, causing shortness of breath and rapid fatigue.^1-3 

LISTEN TO YOUR BODY

Fighting off a bacterial or viral infection is taxing on your body’s energy levels. You might psychologically, even physically, feel ready to start working out again, but your body could still be in recovery phase. Jumping back into an exercise routine can overwhelm an already exhausted body, resulting in extended recovery period and impeding the immune response.³ To avoid reinfection and reduce risk of injury, listen to your body—be conscious of how your body actually feels instead of focusing on those urges telling you to get back to the gym.^1,3 Coughing is also the most rapid way to spread illnesses; you could be putting others at risk.²  To ensure you’re not contagious, wait until you’ve gone 48 hours without a fever. 

A cough from a cold or influenza virus can persist for  two weeks or longer after initial symptoms of illness began.² If not treated correctly, mild respiratory illnesses, such as the common cold, could develop into bronchitis or pneumonia.^2,4 In fact, 33 percent of pneumonia cases start as common colds.⁴ Severe respiratory illnesses, such as bronchitis and pneumonia, should be monitored closely by a physician to avoid serious complications; it could take weeks or months for your body to fully recover, depending on your age, other underlying conditions, and your overall health.⁴ Even if your symptoms have completely subsided, you should ease back into physical activity slowly, rather than immediately jumping back into your pre-illness workout routine. 

MODIFY AN EXISTING WORKOUT ROUTINE

Make it light. The first workout after being sick with a respiratory illness should be light, with duration cut in half, to prevent shortness of breath and fatigue and to gauge energy levels. The degree to which your body has deconditioned, compared to pre-illness fitness level, will be affected by the level of severity and duration of your illness, but even mild respiratory illness will cause some deconditioning, which can make returning to a familiar workout routine difficult.^1,3 Around two weeks of inactivity can lessen the heart’s pumping efficiency, reducing its capacity to take in, transport, and utilize oxygen during exercise.³ Returning to your pre-illness fitness level will be best achieved by gradually increasing the duration and intensity of your workouts. 

Skip a day (or more, if needed). Getting back to your pre-illness fitness level should not be a race. If you’re still feeling drained from a previous workout, don’t hesitate to take a day or more off to recover before working out again.¹ 

Lower the intensity. Like duration, intensity should be reduced, too.¹ Regardless of how accustomed you were, before you got sick, to engaging in frequent, intense physical activity, such as running, cycling, swimming, competitive sports, or aerobics, it is recommended that, after recovering from a respiratory illness, you ease back into a physical activity by starting with moderate-intensity exercises and activities to allow your body time to recondition and adjust.

MODERATE-INTENSITY EXERCISE

According to the World Health Organization, activity that requires moderate effort and noticeably elevates the heart rate is considered moderate intensity.⁵ Thirty minutes of moderate-intensity physical activity daily, five days a week, has been shown to enhance lung function,⁶ reduce inflammation, and improve immune response to respiratory viral infections.^6,7 Regular moderate-intensity exercise has also been shown to increase energy levels and stamina, reduce stress, lower blood pressure, improve cholesterol levels, and decrease risk of certain types of cancers and Type 2 diabetes.⁷ Some examples of moderate-intensity activities include the following:^8–10

Walking. Briskly walking (i.e., 2.5mph) on a treadmill or around your neighborhood is a great moderate-intensity exercise. This type of exercise can be incorporated into daily tasks, such as grocery shopping. Try parking far away from store or work entrances and take the stairs instead of the elevator to add extra steps into your routine.^8-10

Biking. Riding your bike no faster than 10mph is another form of moderate-intensity exercise. Avoid steep hills and tough trails until you feel more fit.^6,8-10 

Yard work. Yes, yard work, as in gardening and mowing the lawn (with a power mower) is a great way to get some moderate-intensity exercise into your weekly exercise routine.  According to the American Heart Association and Harvard T.H. Chan School of Public Health, yard work and mowing the grass work numerous parts of the body and burn calories.¹⁰ 

Housecleaning. The same logic applies to heavy housecleaning, like mopping, washing the windows, and vacuuming. Akin to gardening, a great deal of stretching, bending, and lifting is necessary when you are doing some heavy-duty housecleaning, so work it, baby.^9,10 

INCORPORATE BREATHING EXERCISES  

In addition to moderate-intensity exercise, practicing breathing exercises, even while still sick with a respiratory illness, is beneficial to lung functioning by enhancing lung capacity (the amount of air your lungs can hold); preventing build-up of stale air in your lungs; and improving overall lung efficiency. The American Lung Association (ALA) suggests practicing the following breathing exercises for 5 to 10 minutes every day to provide the body with necessary oxygen and strengthen the lungs, especially if compromised by illness or disease:¹¹

Pursed lip breathing. This simple exercise allows more air to flow in and out of the lungs, keeping the airways open longer.¹¹ While your lips are pursed, inhale through your nose and exhale through your mouth for twice as long. 

Diaphragmic breathing. Place your hands on your stomach diaphragm and breathe in through your nose, making sure shoulders and neck are relaxed.¹¹ Exhale two or three times more slowly than you inhaled, using your stomach to push the air in and out, not your chest. This will retrain your diaphragm to assist filling and emptying the lungs. 

Pranayama. Pranayama is a type of yoga dedicated to maintaining healthy lung function and comprises stretches and poses that synchronize breathing techniques designed to increase brain and body energy.¹² Since most of the poses are minimal in nature, they are perfect for beginners, or for those recovering from respiratory illness, and can be adjusted for comfort. 

BOTTOM LINE

Though engaging in physical activity is healthy, rushing back into an intense exercise routine following respiratory illness can have potentially negative consequences on your health. It is important to focus on acknowledging the overall state of your body rather than chasing the gratification of a good workout. Just like building strength and developing discipline, bodily healing takes time. Give your body time to recover properly, and it will reward you with strength, stamina, and overall health. 

SOURCES

1. Harvard Medical Publishing site. How long should I wait after the flu before resuming exercise? https://www.health.harvard.edu/staying-healthy/how-long-should-i-wait-after-the-flu-before-resuming-exercise.
   Accessed 24 May 2020. 
2. Harvard Health Publishing Site. The respiratory tract and its infections. Feb 2010. https://www.health.harvard.edu/newsletter_article/the-respiratory-tract-and-its-infections. Accessed 24 May 2020.  
3. Simpson RJ, Campbell JP, Gleeson M, et al. Can exercise affect immune function to increase susceptibility to infection?. Exerc Immunol Rev. 2020;26:8 –22.
4. American Lung Association site. Pneumonia treatment and recovery. Updated 6 Mar 2020. https://www.lung.org/lung-health-diseases/lung-disease-lookup/pneumonia/treatment-and-recovery. Accessed 24 May 2020.
5. World Health Organization site. Global strategy on diet, physical activity and health. https://www.who.int/dietphysicalactivity/physical_activity_intensity/en/. Accessed 24 May 2020.
6. Luzak A, Karrasch S, Thorand B, et al. Association of physical activity with lung function in lung-healthy German adults: results from the KORA FF4 study. BMC Pulm Med. 2017;17(1):215. 
7. Martin SA, Pence BD, Woods JA. Exercise and respiratory tract viral infections. Exerc Sport Sci Rev. 2009;37(4):157–164. 
8. Mayo Clinic. Moderate Exercise Yields Big Benefits. 4 Jan 2008. ScienceDaily site. https://www.sciencedaily.com/releases/2008/01/080104123421.htm. Accessed 24 May 2020. 
9. Harvard T.H Chan School of Public Health site. Examples of moderate and vigorous physical activity. https://www.hsph.harvard.edu/obesity-prevention-source/moderate-and-vigorous-physical-activity/. Accessed 24 May 2020.
10. American Heart Association site. American Heart Association recommendations for physical activity in adults and kids. Updated 18 Apr 2018. https://www.heart.org/en/healthy-living/fitness/fitness-basics/aha-recs-for-physical-activity-in-adults. Accessed 24 May 2020.  
11. American Lung Association site. Breathing exercises. Updated 24 March 2020. https://www.lung.org/lung-health-diseases/wellness/breathing-exercises. Accessed 24 May 2020.
12. Sengupta P. Health Impacts of Yoga and
    Pranayama: A State-of-the-Art Review. Int J Prev Med. 2012;3(7):444–458.