The answer to this question varies from one person to the next.  Its really how you feel. I’ve always felt that if your coughing or hacking up a lung with some lung/chest pain, don’t workout. Its more respitory-related and not such a great idea. If you’re running a fever–don’t workout.

If its a head cold and all you have is a runny nose, then its not such a big deal. But always check with your doctor and always gauge your energy levels. Working out during a cold could prolong the recovery time, not to mention spread those germs in the gym.

Use your best judgment. Maybe taking a walk outside will help clear your sinuses. Missing a few days to recover isn’t the end of the world and you’ll most likely come back stronger.