What if you really don't want to miss a day's training you've been planning for a long time, but you wake up that morning with a bad cold? Or if you really need to shed the pounds gained from overeating during the holidays?
Should you go ahead and complete you training session anyways or take the day off?
To answer that question, you need only a little common sense. You will probably be tired with below-par muscle strength if you are ill so you might as well accept that, as a result, your workout will be sub-optimal. What's the point?
you will actually be in better shape if you wait a day or two and rest, as you can then train more intensely. Not to mention that working out when you're sick can be dangerous. For example, though you may think you only have a common cold, you might actually have something like a 'Coxsackie' virus,which can infect your heart and possible cause sudden death as you train.
If you will be able to train strenuously in a few days, Why tempt fate and risk serious illness now?
If you remain unpersuaded by these first two arguments for rest, then use what exercise and health experts call the 'neck check' to determine whether or not you can train.
If all of your symptoms are above the neck (stuffy or runny nose, sneezing, watery eyes, and/or scratchy throat) then it's okay to start your workout
at about half speed. Then if you feel better after 10 minutes or so you can increase your intensity and finish your workout.
If not, then some chicken soup, vitamin C, fluids, and a few days rest are advisable.
Do NOT work out if your symptoms are
below the neck (aching muscles, a hacking cough which seems to resound deep
within your chest, nausea, vomiting, and/or diarrhoea) or if you have a fever.
It can be dangerous to work out under such conditions, and rest will help you to recover much faster.