Exercise when you’re sick

Originally written for www.stuff.co.nz, published 5 June 2018

It’s that time of the year again, you’ve just re-established a regular exercise routine (again), but you can feel yourself coming down with the sniffles – how do you know if it’s OK to exercise and sweat it out or if you should take a break?

It all depends on what sort of exercise you’re going to do and what kind of sick you are.

When you’re feeling good, a hard workout encourages a physical stress response in your body and adaptation to this is how we get fitter and stronger.

When you’re sick, this sort of stress can be too much for your immune system. But depending on your symptoms it can still be useful do some physical activity.

Low intensity activities like walking, stretching, tai chi, yoga and gardening, which are not intense enough to compromise recovery, have been shown to increase immunity and help you recuperate from illness more quickly.

Exercising too much or too little can weaken your immune system but consistent exercise and resistance training over time, in the right amounts, can strengthen it. However, if you’re feeling sick, a single high intensity session or long duration cardio can impair your immune function and lengthen recovery time.

What you consider to be moderate or high intensity is individual and depends on many things like your current level of fitness and regular exercise routine. Be guided by your own perceived level of exertion and note that a low to moderate intensity workout should leave you feeling good and energised while a high intensity workout will leave you wasted.

A general rule for whether to exercise when you’re feeling sick is the neck check. If your symptoms are above the neck – sneezing, sore throat, runny nose – then it’s usually OK to work out but keep the intensity low and pay attention to how you’re feeling.

Below the neck symptoms – coughing, aching muscles, fever and fatigue, diarrhoea and vomiting – indicate it’s time to take a few days off and get back to the exercise when your symptoms or infection are gone. Exercise when you feel like this can make things worse.

The other thing to consider is not spreading your germs. It’s best to stay away from the gym (and work) on the days you feel your worst, you won’t get any sympathy for turning up as no one wants to be around you. If you must, and if it’s appropriate, do your low intensity activity from home. With a common cold, you’re typically contagious for about 5 full days, and your germs spread most easily during your 2 to 3 more symptomatic days. Cold germs can live on hard surfaces like dumbbells for hours.

All in all, the right amount regular exercise while healthy will boost your immune system and protect you from illness. When you’re not feeling so good, listen to your body, evaluate your symptoms and plan your activity accordingly.