Dizzy After a Tough Workout? These Are the 3 Most Common Reasons Why

woman drinking water after workout


Cardio workouts require a serious amount of energy, and it’s normal for them to leave you feeling a little depleted. However, your cardio workout should never make you feel dizzy (if you're taking the proper precautions for your body, that is).

If workout dizziness is something you’ve experienced before or are concerned about experiencing in the future, we have the info you need to help prevent it from happening. To give the best sense of how to avoid it, we asked Nicola Finley, MD, and NASM-certified personal trainer Emilie Nasseh about what the common causes of workout dizziness are, and how to they can be mitigated either in advance or in the moment while working out.

Meet the Expert

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Forgetting To Breathe

While remembering to breathe seems like such a basic concept that it’s almost silly, forgetting to breathe is actually a common reason for workout dizziness. Nasseh notes that “When you're exercising, your muscles are eating up a lot of oxygen. If you aren't breathing, your heart may not be pumping enough blood, which may lead to dizziness.”

How To Prevent It

Getting through a cardio workout takes brain power, but to prevent dizziness caused by forgetting to breathe it’s key to use a bit of that brain power to focus occasionally on your breath. Make sure that you aren’t holding it, are regularly pausing to catch your breath when needed, and that you’re inhaling and exhaling deeply enough to get the needed oxygen into your lungs to continue to power your exercise.

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If you’ve ever been to a cardio workout class, there is one consistent accessory that everyone brings: a water bottle. That’s because cardio makes you sweat, and it’s important to continually replenish the water you’re losing. Nasseh says, “When exercising, your body temperature rises and you may lose a lot of water, which may lead to dizziness,” if you aren’t drinking enough as you go.

How To Prevent It

Dr. Finley puts it simply: you can avoid dizziness caused from dehydration “by staying well-hydrated with water.” She says that “the addition of electrolytes to water can be beneficial” as well because that will help you replenish the electrolytes you’re also losing through sweating. In terms of quantity, Emilie suggests “drinking 4-6 ounces of water every 10-12 minutes during your workout” to help prevent dizziness. She stresses, “Staying hydrated during your workout is overly important and you must continue to do so throughout!”

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Low Blood Sugar

While doing cardio with a stomach full of just-eaten food isn’t a great idea (because it can lead to poor digestion and make you feel sluggish), doing a cardio workout on an empty stomach instead can be just as problematic. That’s because in order to properly give your all to your workout, your body needs enough fuel in its system. You wouldn’t try to drive your car without gas in it, and your body is no different: it needs enough nutrients to be able to do what you’re asking of it. Working out lowers your blood sugar, so it’s imperative that your blood glucose levels haven’t dipped low before you even begin your workout.

How To Prevent It

Similar to the other reasons you may be experiencing dizziness from a cardio workout, lack of fuel or low blood sugar is an easy thing to prevent. Dr. Finley notes that “a good strategy to maintain an adequate blood sugar level is through healthy nutrition before exercising or during exercise.” What does this mean specifically? Emilie suggests “Eating a high carb snack about an hour before your workout” because that “can assist in preventing dizziness.” She says, “Carbohydrates keep you properly fueled for your workout, and may prevent you from getting dizzy.”

A Final Word

The above reasons are the most common causes of workout dizziness, and hopefully implementing the preventative measures suggested will make it so that you never get dizzy from cardio workouts. However, it’s important to also mention that your workout dizziness could possibly have a more serious underlying cause. Dr. Finley cautions that even though “heart conditions like arrhythmias and structural heart abnormalities are less likely to present with dizziness after exercise, these more serious causes should still be considered.” If workout dizziness is something that happens to you despite taking simple preventative measures like the ones detailed here, it should be discussed with your doctor before you continue with your exercise regime. 

Article Sources
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  2. Lacey J, Corbett J, Forni L, et al. A multidisciplinary consensus on dehydration: definitions, diagnostic methods and clinical implications. Ann Med. 2019;51(3-4):232-251.

  3. Thomas DT, Erdman KA, Burke LM. American college of sports medicine joint position statement. Nutrition and athletic performance. Med Sci Sports Exerc. 2016;48(3):543-568.

  4. Chiang S-L, Heitkemper MM, Hung Y-J, Tzeng W-C, Lee M-S, Lin C-H. Effects of a 12-week moderate-intensity exercise training on blood glucose response in patients with type 2 diabetes: A prospective longitudinal study. Medicine (Baltimore). 2019;98(36):e16860.

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