Should you exercise when you have a cold? One theory is that moderate aerobic exercise improves immunity and protects you from colds and other infections, whereas intense exercise (like training for a marathon) can depress the immune system.
The effect of exercise on your immune system is complex. The rule of thumb when deciding to exercise if you’re not feeling well is to check your symptoms. If it seems like just a cold, exercise will do your body more help than harm.
But if you are experiencing flu-like symptoms, such as muscle aches and particularly a fever, then your body needs rest until the symptoms pass. Overall, the risks of leading a sedentary lifestyle far outweigh the risks of working out while you have a cold