Why do I feel exhausted and sick during exercise?


If your body is feeling sick and exhausted during exercise then more than likely you are experiencing signs of dehydration.  Many individuals do not get enough water so be sure to drink and drink often.  Striving to drink a glass of water each hour of your workday which will result in 64 ounces of water keeping your body nice and hydrated!


Wendy Batts
A lot of factors can contribute to why you may feel ill during exercise. The first things to check are nutrition, hydration and energy levels.

Nutrition: do you have fuel in the tank? A lot of exercisers think you’re supposed to work out on an empty stomach and this isn’t true. So if you go into a workout with no fuel on board, this can possibly cause you to feel bad and perform poorly. Did you eat TOO much before a workout? The opposite can be true sometimes as well. Working out with full bellies can be counterproductive to how you feel during a workout.

Hydration: are you drinking enough water throughout the day and during the workout? Slight to moderate hydration can lead to drops in exercise performance.

Energy levels: How are you feeling overall? Are you fighting a cold? Are you getting enough sleep? Are you just flat-out tired from a rough day at work? All of these things can contribute to feeling exhausted and sick.

If fatigue may seem like it’s coming from something other than your daily habits, please check with your healthcare provider ASAP because a more serious medical condition could be underlying your exercise induced exhaustion, nausea, etc.
If you do feel exhausted and sick you are not exercising properly. At the end of one of my workouts, I want you feeling tension free/floaty and energized. Make sure you are hydrated, take your body weight cut it in half and that is how many ounces you need to consume consistently every day. Don't workout on a completely empty stomach. Eat something light and healthy 45 minutes before you workout.

Heidi Skolnik, MS
Sports Medicine
My guess is that you are working at an intensity for which you are not yet conditioned for. In your eagerness to get fit, you may be working too hard. Pacing, hard/easy days, cross training and using a heart rate monitor may help you to find just the right intensity so that exercising feels invigorating instead of making you sick!!   Another thought is that you are dieting and not eating enough or drinking enough and that this can contribute to feeling exhausted. Try to eat about 15 grams of carbohdrate (a few crackers or 1/2 of a banana) and 6-8 oz. of water about an hour before workingout and see if that helps at all. Still, it is always a good idea to check with your medical provider and rule out any serious concerns before proceeding. 
Dr. Michael Roizen, MD
Internal Medicine
You are probably feeling exhausted and sick during exercise due to dehydration or not having enough water to read a newspaper through your pee. Our bodies are made of about 75% water, and levels have to be maintained to function properly. Your body loses water through respiration, urination, and exercise. Drink 64 ounces a day. Drink more with intense exercise.

Continue Learning about Types Of Exercise

Types Of Exercise

Types Of Exercise

Exercise provides many health benefits - from fitness to increased physical and mental energy. In order to prepare yourself for a exercise routine, you need to research which exercise is right for you and how to fit a new exercise ...

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.