Take a break and get some rest! It will help you get well sooner and it might end up improving your results in the long term. When you’re sick, your body uses its recovery properties to fight the illness. When you exercise, you use these same properties to recover. To your body, trying to exercise when you’re sick is effectively the same thing as overtraining. You won’t be able to recover from exercise, rendering it useless, as well as increasing the risk of making your illness worse and lengthening your downtime.