Important caveats: 1/ Too much exercise increases the chances of catching a cold as well as increasing the severity (there is research on this) 2/ Gyms are full

Important caveats: 1/ Too much exercise increases the chances of catching a cold as well as increasing the severity (there is research on this) 2/ Gyms are full of people and you touch a lot of the surfaces - so that may offset the effect (this I'm guessing)