It is generally known that training is some kind of guarantee for good health. As we engage in physical activity we become stronger, more durable, more flexible and far more capable of dealing with everyday issues. However, there are also occasions where training may have the opposite, rather negative, impact on our physical health and these include the times we are ill.

During exercise your heart rate as well as your body temperature rises, your energy consumption drastically increases, and you lose body water fluid body due to sweating. All this is completely harmless for a healthy individual, but when we are struggling with a stubborn virus these effects can be rather dangerous for our bodies. For example, if you experience or have a confirmed fever, this means that your body temperature is already high. Further elevation in temperature can therefore be bad for you. When our body is working hard to get rid of a virus it is important that we keep the water level in our bodies stable. Loss of body fluid in the form of sweating can in the worst case lead to dehydration.

Exercise itself exposes our bodies to short term stress and with the purpose of becoming more resilient it adjusts gradually to the challenges we put it up to. Influenza and other cold viruses are also sources of stress that our body must handle and defeat. We could therefore say that training during periods of illness means that we force it to fight two different battles in two different arenas, all at the same time.

The duration of our recovery depends on how we act during the process.

An exhausting workout is of course not a good idea but moderate, low-intensity training may actually be good for you. There are studies that shows that exercise on a moderate level does not necessarily have to worsen or even maintain the symptoms, but it is in this context referred to restrained and cautious activity. High intensity training such as power lifting or demanding aerobic exercise can on the other hand have a direct negative impact on the immune system.

In addition, we should also ask ourselves whether we are contagious. If our training includes direct or indirect contact with other people such as gym, group training or team sports it is important that we also take these people in consideration. It is possible that we through use of equipment and machines or simply through our mere presence pass it all on. If you suspect that you are contagious (or just want to prevent future disease) it is advisable to keep your hands clean, wipe off machines after use and keep some distance to other individuals.

When is it safe to return to training?
Before you decide to exercise or not, you should first scan off your own symptoms. Do you experience an irritated throat, mild headache, a constantly runny nose, but have energy in general? As long as your soreness is located to the upper part of the throat it should be quite safe to go back to exercising.If you feel capable of working out but are not thoroughly cured you should focus on moderate intensity, increased rest between sets, additional amounts of water during the session, and a good rest afterwards. Keep your symptoms under surveillance at all times to prevent you from aggravating them.

When is it harmful?
If you experience symptoms such as pain in your muscles or chest, fever, diarrhea and/or pain as well as redness in the lower part of the throat, you are better off just staying at home. Heavier physical activity in this situation will certainly just drag out the whole process rather than help you reach any fitness goals.