Any form of training will involve the interplay between the three energy systems – alactic, lactic and aerobic. At a time when we are at a high risk of some form of infection, it is important that we moderate our training loads. Heavy training can potentially compromise the function of the immune system, whereas light and medium training can actually stimulate the immune system. Although it is tempting to get rid of some frustration and cabin fever, hold back and don’t risk it. You will still get plenty of endorphins and training effect from a session just below your threshold.