A: Let your symptoms be your guide. A slight sore throat or runny nose may require you to back off for a day or two but don’t confine yourself to your bed and assume the worst. However, you must also remember that prolonged, intense exercise can decrease immune function and make you more susceptible to bacterial and viral based sickness so it's equally as important to listen to your body and respond accordingly.
But muscle can’t turn into fat, just like mud can’t turn into gold. If you quit lifting, your muscles mass will decrease over time because there’s no training to stimulate your body to keep it. And your body-fat level will increase if you don’t start eating less (since you burn less). The obvious solution when you stop lifting is to also stop eating so much.
I HATE that the resistance training community can be so tribal. I have been preaching to bodybuilders for years about the benefits of powerlifting, or Olympic lifting or kettlebells or even Crossfit style conditioning and many have been receptive. Learn from each other and achieve levels of fitness you simply could not have otherwise. Don’t brush off bodybuilding wisdom…it could be the missing factor in your program.