Should you workout when sick? Well, it depends on a lot of factors. That’s a common question I often get from my clients both online and offline. Most people experience a bit of discomfort on any particular day, the way one feels before the sickness overwhelms the body’s defences, and turns from minor irritation to a full-fledged cold or fever, with watery eyes, soaring temperatures, shivering body and host of other unwanted symptoms.

Exercising will you’re sick won’t certainly hurt your immune system. But this is not a generalized statement. How sick you are; what is the intensity of the workout; what’s your general immunity, like do you feel sick often; and a lot of questions needs to be answered, and that’s why the decision should you workout when sick, will depend on an individual case to case basis.

There is no study as such which I found on this topic, but a conclusion made from collective information from science and personal experience will certainly help. If you’re suffering from a slightly running nose or sore throat, then you may workout, but moderately. High intensity workout or heavy resistance training sessions will not form the part of your workout in any case, where you fear illness. May be going for a relaxing walk, or a cycling session, or even a light swim, would be fine on these days.

However, if you’re having worsening symptoms like heavy running nose, soaring body temperature, body pain, coughing, joint aches & pains, etc. then you are better off exercising at all and relaxing, in your cozy bed, maybe with a cup of hot green tea with ginger and turmeric, or black coffee with cinnamon and turmeric to give you the much-needed antioxidant boost. The best bet here would be to sleep off, as much as you can rather than thinking should you workout when sick. Lying in the bed and working on your laptop or cellphone, won’t make things any better. Take complete rest, and it starts from more sleep.

You would now be probably fine, in a day or two, and you can again resume the exercises, but do not start full-on with high intensity sessions. Your body needs time to recover. Start slow, and progress gradually.

Dr. Howard LeWine, Editor in Chief, Harvard Men’s Health Watch, suggested that Most healthy people who have cold or mild bronchitis without fever or significant cough can continue to exercise during their illness. However, you initially want to cut your intensity and duration in half. If you feel good later in the day after your lighter workout, you can gradually increase how much you do during your next session. But if you feel exhausted after exercising, take off an extra day before working out again.

So should you workout when sick? With the flu or any respiratory illness that causes high fever, muscle aches, and fatigue, wait until the fever is gone before getting back to exercise. Your first workout back should be light so you don’t get out of breath, and you want to progress slowly as you return to your normal routine. You may be tempted to ramp it up, but it’s best to go low (low intensity) and go slow (short duration).

Understand that, when you do intense training sessions, you do not get stronger there and then. Heavy training awakens a stress response in the body, and you eventually adapt to this stress by getting stronger. But when you’re sick, the intense workouts are putting too much load on the immune system, for it to handle.

However, even when you’re mildly sick, you don’t have to be completely sedentary. Active rest is always a better option when the question is should you workout when sick. Going for light walks, a bit of yoga, etc. will help you ward off the diseases much faster.

Athletes engaged in competitive sports need extreme practice sessions, multiple times a day. When you’re engaged in such a high amount of physical workload, the body is vulnerable to various immune infections. A 1994 study in the journal Medicine & Science in Sports & Exercise, by researcher D.C. Nieman (https://bit.ly/2SlAPJL), suggested that unusually heavy acute or chronic exercise is associated with an increased risk of upper respiratory tract infections. The risk appears to be especially high during the one or 2-wk period following marathon-type race events. Among runners varying widely in training habits, the risk for upper respiratory tract infection is slightly elevated for the highest distance runners.

According to Nieman, “Clinical data support the concept that heavy exertion increases the athlete’s risk of upper respiratory tract infections because of negative changes in immune function and elevation of the stress hormones, epinephrine, and cortisol. On the other hand, there is growing evidence that moderate amounts of exercise may decrease one’s risk of upper respiratory tract infections through favourable changes in immune function without the negative attending effects of the stress hormones.”

Researcher T.G. Weidner & team, in a 1998 study in the journal Medicine & Science in Sports & Exercise (https://bit.ly/3cQyv6W), also found that moderate exercise training during a rhinovirus-caused upper respiratory infection, do not alter the severity and duration of the illness.

Nieman further in a 2000 study, in the journal Medicine & Science in Sports & Exercise (https://bit.ly/3kZ6mh4), found that, for several hours subsequent to heavy exertion, several components of both the innate and adaptive immune system exhibit suppressed function. However, the immune response to heavy exertion is transient. Though data suggest that, endurance athletes are at an increased risk for upper respiratory tract infection during periods of heavy training and the 1 – to 2-week period after race events.

Prof. Nieman suggested that, diminished neutrophil function in athletes during periods of intense and heavy training. Following each bout of prolonged heavy endurance exercise, several components of the immune system appear to demonstrate a suppressed function for several hours. This has led to the concept of the “open window,” described as the 3- to 12-hour time period after prolonged endurance exercise when host defence is decreased and the risk of URTI is elevated

The majority of athletes, however, who participate in endurance race events do not experience illness. Of greater public health importance is the consistent finding of a reduction in upper respiratory tract infection risk reported by fitness enthusiasts and athletes who engage in regular exercise training while avoiding overreaching/overtraining.

In a 2007 study in the Journal of Applied Physiology, researcher Michael Gleeson, from the School of Sport and Exercise Sciences, Loughborough University, UK (https://bit.ly/3cP1zM8), Regular moderate exercise is associated with a reduced incidence of infection compared with a completely sedentary state. However, prolonged bouts of strenuous exercise cause a temporary depression of various aspects of immune function (e.g., neutrophil respiratory burst, lymphocyte proliferation, monocyte antigen presentation) that usually lasts app. 3-24h after exercise, depending on the intensity and duration of the exercise bout. Post-exercise immune function dysfunction is most pronounced when the exercise is continuous, prolonged (>1.5hrs), of moderate to high intensity (55–75% maximum O2 uptake), and performed without food intake. Periods of intensified training (overreaching) lasting 1wk or more may result in longer-lasting immune dysfunction. Although elite athletes are not clinically immune deficient, it is possible that the combined effects of small changes in several immune parameters may compromise resistance to common minor illnesses, such as upper respiratory tract infection.

A 2012 study in the Annals of Family Medicine, by Dr. Bruce Barrett & team (https://bit.ly/2GqYsy6), evaluated potential preventive effects of meditation or exercise on incidence, duration, and severity of acute respiratory infection (ARI) illness, on over 150 adults, aged 50yrs or more. Researchers observed substantive reductions in ARI illness among those randomized to exercise training, and even greater benefits among those receiving mindfulness meditation training.

The conclusion of should you workout when sick is given here. Most researchers have given the famous J-shaped curve, comparing immunity and exercise. This curve simply shows that being sedentary or overtraining, both can lower immunity. Using a J-shaped model for exercise & infection, researcher C.E. Mathews & team, in a 2002 study in the journal Medicine & Science in Exercise & Sports (https://bit.ly/3jnTDnz), examined differences in URTI risk between physically inactive and moderately active, 547 healthy men & women aged 20-70yr, and concluded that moderate levels of physical activity are associated with a reduced risk for URTI.

Also, your life and health are not just influenced by workout related stresses. Every day there are many stressful events you face. Be it environmental (pollution, traffic jams, etc.), psychological (family, office, relationships, etc.), lifestyle (medicines, poor diet, etc.). The more stress of different types your body faces every day, the faster you are likely to get sick.

For e.g. you’re a long-distance runner, living in a polluted city, plagued with traffic jams. On top of that, you’re having family issues and work-related stresses. You are much more likely to fall sick than someone living in a cleaner environment with minor social issues.