The quick and easy answer, maybe. If you're really feeling bad -- i.e., you have a fever, you're hacking up green, skip a day. Let your body use all its resources to fight whatever bug is attacking you. Drink smart liquids. Ginger tea, and yep, a low calorie hydration mix. When you're sick you sweat, and dehydration feels just as crap as being sick. Now on the other hand if your feeling stuffed up, have a little congestions, a teeny tiny sore throat and really wanna get out there, go go for it. If you feel like you are getting sick, but maybe are milking your symptoms to avoid exercising, get out there. Studies have show that the endorphin rush that follows a workout session can even make you feel better, for a little while. Getting your heart pumping and body sweating gives your body a physiological pep talk, and beats slumming around in your PJ's all day, any day. When you get out there, listen to your body. If working out seems to exaggerate your symptoms, or the act of getting your heart rate up is exhausting, you probably need to back it off. Make sure you're hydrating. This will help you through your workout, but it will really help you from feeling "creaky" after you work out. When you're sick your body uses a lot of energy to fight off whatever you got. That also means you're going to need more sleep, and more fluids. Also, if you're hitting the gym, be careful, you could end up spreading germs to others, or in your immune weakened state, you're more susceptible to picking up things from others.... so spray down that elliptical machine before and after you hop on it, and wipe down the weights. Just pay attention to how you're feeling. One day spent resting when you need it, is going to help you bounce back quicker than slugging it out at 50% for days to come. Our go-to sick day hydration option? Gu Brew Grapefruit.