Should You Exercise When You Feel Sick?

Should You Exercise When You Feel Sick?


Hi Everyone!

Many of you have started new routines that have included an exercise regimen….WooHoo!!!  What happens if you start to feel sick?  You really don’t want to break your routine but you have to ask yourself, is it safe to exercise when you’re feeling sick? 

It depends.  Most Doctors will tell you, you can exercise if you’re sick from the neck up.  If you have a sore throat, stuffy nose, itchy/watery eyes…go ahead and exercise.  If you have a fever, muscle fatigue, body aches or respiratory problems…you should do nothing but rest.

How should you exercise while you’re sick?  Stick to low to moderate exercises:

  • ·         Brisk walk or slow jog outside for 30-60min


  • ·         Yoga or pilates


  • ·         Body-weight exercises at a slow pace (squats, lunges, push-ups, planks…)

According to MedlinePlus, exercise helps your immune system fight off simple bacterial infections, viral infections and decreases your chances of developing heart disease, osteoporosis, and cancer.

There are several theories as to why exercise boosts your immune system:

  • Physical activity may help by flushing bacteria out from the lungs (thus decreasing the chance of a cold, flu, or other airborne illness) and may flush out cancer-causing cells (carcinogens) by increasing output of wastes, such as urine and sweat.
  • Exercise sends antibodies and white blood cells (the body’s defense cells) through the body at a quicker rate. As these antibodies or white blood cells circulate more rapidly, they could detect illnesses earlier than they might normally. The increased rate of circulating blood may also trigger the release of hormones that “warn” immune cells of intruding bacteria or viruses.
  • The temporary rise in body temperature may prevent bacterial growth, allowing the body to fight the infection more effectively. (This is similar to what happens when the body has a fever.)
  • Exercise slows down the release of stress-related hormones. Stress increases the chance of illness.

There are also times when exercise can weaken your immune system.  Ben Greenfield, who has competed in several ironman triathlons and is the author of “Beyond Training” says,

                “…nearly every time I finish an Ironman triathlon, I get sick 5-7 days later – and research has shown that as few as 90 minutes of high-intensity endurance exercise can make you more susceptible to illness for up to 3 days after the session.

The reason for this is a release of certain hormones that can cause a temporary decrease in the proper function of the immune system. When you perform a hard exercise session, you significantly increase the release of cortisol and adrenaline, which are your body’s “fight and flight” stress hormones. This can raise blood pressure and cholesterol levels, and simultaneously suppress the immune system.

As you probably guessed, if you are already sick with a cold or respiratory infection, high intensity exercise such as heavy weight lifting or very long exercise such as marathon training can further weaken the immune system”.

When you’re feeling under-the-weather, remember the following:

  1. If you’re sick from the neck up, you exercise at a low to moderate intensity for 30-60min
  2. If you’re sick from the neck down, fever, fatigue, respiratory problems…REST!!
  3. To avoid getting sick and boost your immune system, exercise 3-5 days weekly with a healthy balance between low, moderate and high intensity workouts for no longer than 60min

Yours in Health and Wellness,


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