Exercise is supposed to make you feel energized — not exhausted. But if you're feeling lethargic after your workout, you're not alone. When you exercise, you burn calories and expend energy. Depending on the length and intensity of your workout, you may be physically taxing your body, which means you need water, nutrients and rest to recover. Here are some reasons you might feel especially tired after a workout and what you can do about it.
Causes of Tiredness After a Workout
Many different factors can contribute to that sluggish feeling you're experiencing after working out. Some of the most common culprits include:
1. You're Pushing Yourself Too Hard
While it may sound obvious, the more intense your fitness routine is, the more tiredness after exercise you'll typically feel afterward. This is because of the way your body meets its energy needs during exercise.
During low- to moderate-level exercise, the body harnesses energy from a molecule called adenosine triphosphate, or ATP, which uses oxygen in the body to keep you moving. Staying at this intensity level allows you to work out while also effectively recovering afterward.
When your regimen is too strenuous, however, the demand for ATP is higher, and it can leave your energy reserves depleted and may leave you with extreme fatigue after working out.
2. You're Not Eating Correctly
Keeping your body properly nourished helps you feel good after you exercise. Your diet has a direct impact on your muscles' ability to recover after a workout and on your energy levels after the fact.
Be sure to skip overly fatty foods as well as meals that are high in fiber before you exercise. In addition, spicy foods or drinks with carbonation can be tough on the stomach and should be avoided. In general, the heavier the preworkout meal, the more difficulty you may have recovering from it, which is why you may feel sleepy after a morning workout.
3. You're Not Drinking Enough Water
Regardless of your fitness level or preferred exercise, drinking enough water during and after your workout is important. When you exercise, your body loses large amounts of fluid through sweating.
In addition, breathing hard, especially in colder weather, can affect fluid levels. As a result, it's easy to become dehydrated if you don't drink water frequently. When the body reaches a state of dehydration, tiredness or lethargy can occur and your muscles can't adequately recover.
4. Possible Medical Condition
In most cases, feelings of fatigue after exercise are easily improved by modifying your pre- and post-workout routine or by altering your fitness regimen. However, this isn't always the case.
Certain medical conditions can have a profound effect on your body's ability to recover from a workout, including diabetes, chronic fatigue syndrome, COPD, multiple sclerosis and sleep apnea. Issues with your thyroid or heart may also be to blame. If you have any concerns, it's best to speak to your physician so that these conditions can be ruled out.
Why You Might Feel Sleepy After a Workout
It's important to differentiate between feeling tired or worn down after exercise and feeling the need to go back to sleep. While it may seem like splitting hairs, distinguishing between the two sensations can help you home in on their root cause.
If you feel sleepy after a workout (not just tired), one of these three things may be the reason.
1. The Time of Day
Believe it or not, your body's natural circadian rhythm has a strong impact on which time of day is best for you to work out. Your body's internal clock, which is influenced by the earth's rotation, plays a huge role in regulating your internal temperature, blood pressure and heart rate.
These, in turn, influence your ability to complete and recover from a workout. Just as a night owl may have a hard time focusing on a work-related task in the early-morning hours, an early bird may become more easily exhausted by a late-night workout. Failure to listen to your body's natural rhythms can lead to exhaustion after the fact.
2. Inadequate Sleep
Sleep and exercise go hand in hand. Regular exercise has been shown to improve sleep quality and feelings of fatigue during the day. On the other hand, failure to get an appropriate amount of sleep the night before a workout can cause the same amount of exercise to seem more challenging than the last time you tried it.
In addition, getting enough sleep causes your energy reserves to be replenished. A sleep-deprived individual who already lacks energy and attempts to work out can become extremely sleepy after exercising.
3. Possible Medical Condition
There are a variety of medical issues that can lead to feelings of sleepiness. Exercising with one of these can further exacerbate your fatigue and make you feel as if returning to bed is the only option.
In addition to the conditions noted earlier, mental health issues, fibromyalgia, mononucleosis, hepatitis and many other conditions can lead to extreme fatigue. Taking certain supplements or medications can also contribute to the problem. Consult your health care provider early on to help you manage your sleepiness and make regular exercise more manageable.
5 Ways to Reduce Tiredness After Exercise
In most cases, a few simple changes to your daily routine can help improve or prevent fatigue and sleepiness after your workout. Try these five tips to improve your well being after you exercise.
1. Listen to Your Body
Even if you're only exercising once or twice a week, don't blame yourself for getting tired. Instead of beating yourself up for being out of shape and forcing yourself to march back into the gym the following day, take the cues your body is giving you. This way you won't feel exhausted after spin class when you decide to go.
When you're tired, your body is demanding rest and nutrients to rebuild your muscles and energize you. Although your workout might have been what pushed you over the edge, chances are you're neglecting your body before you even hit the gym.
2. Eat Before and After Your Workout
It's imperative to eat nutritious foods both before and after you exercise to fuel your body and replace lost calories, vitamins and minerals. About 45 to 60 minutes prior to a workout, try a small meal of simple carbohydrates, like a banana or strawberries, and a protein bar or shake. Be sure to avoid eating too soon before your exercise routine, however, as this may lead to stomach discomfort.
If you plan on exercising for less than an hour, eat carbohydrates that will provide a quick burst of energy, like a handful of grapes or a small amount of fruit juice. If you're working out for longer than an hour, meals like an English muffin with peanut butter or a bowl of Greek yogurt with a handful of granola can help provide you with the energy to sustain your routine.
Within 45 minutes of your work out, refuel your body with a snack that contains both protein and carbohydrates, like oatmeal with fruit and almond butter. This snack will replace the glycogen stores that have been depleted during exercise, providing an energy boost.
3. Hydrate Yourself Properly
Staying hydrated is crucial to preventing dehydration as you sweat off fluid while you exercise. This involves drinking plenty of fluids before, during and after your workout.
One to two hours before you begin your workout, start drinking water. During this time, try to take in between 15 and 20 ounces. Approximately 15 minutes before you start, drink another 8 to 10 ounces. While you work out, drink 8 ounces of water for every 15 minutes of exercise. Afterward, replace your fluids by drinking another 16 to 20 ounces for each pound you lost while working out.
4. Get Plenty of Sleep
If you've been burning the candle at both ends, exercise might be impossible. If you're spending your nights studying, working or taking care of your family instead of sleeping, you're depriving your body — and this can make you feel even more tired after a workout.
Get seven to nine hours of sleep a night to allow your muscles to rest and rebuild. Getting too little or too much sleep can lead to tiredness after a workout (not to mention throughout the rest of the day).
5. Talk to Your Doctor
In rare cases, fatigue or exhaustion may be the result of a serious medical condition, like those listed above or numerous others. If you have any medical symptoms in addition to your exhaustion after exercising, contact your doctor.
- University of New Mexico: Optimize Endurance Training
- Science Aid: Energy and Exercise
- Healthline: Pre-Workout Nutrition: What to Eat Before a Workout
- Healthline: Post-Workout Nutrition: What to Eat After a Workout
- WebMD: Water Tips for Efficient Exercise
- CBS News: What to Eat Before a Workout – and Foods to Avoid
- Mayo Clinic: Fatigue Causes
- Shape: Is It Better to Sleep In or Work Out?
- National Sleep Foundation: What Happens When You Sleep?
- WebMD: What's the Best Time to Exercise?
- Medical News Today: Fatigue: Why Am I So Tired and What Can I Do About It?
- Everyday Health: What to Eat Before and After Your Workout
- National Sleep Foundation: How Much Sleep Do We Really Need?