The Biggest Reasons You Feel Tired During Your Workouts

You’re here because you want to know why you feel so tired and drained during a workout.

Maybe you’re having trouble doing workouts that you used to breeze through without feeling tired.

Maybe more and more you’ve noticed your energy “dip” in the middle of exercising – and you want to know why.

Maybe you’ve just been feeling sluggish and not at your best at the gym, and you want to figure out what to do about it.

more: The 9 Biggest Reasons You’re Tired All The Time

Whatever the reason – you want to know why you feel so tired during your workout – and this article is here to help.

The Top Reasons You Feel Tired During Your Workout

The main reasons you’re going to feel exhausted and drained in the middle of a workout have to do with your body, and the state that your body is in. If you’ve been in great shape and are now suddenly feeling drained during workouts, then it probably has to do with something new – like a change to your sleep schedule, allergies, working out too much, not getting enough water, or a change to your diet. If you always feel sluggish during workouts, it could be because of your glycogen production, or thyroid, or an underlying condition like anemia or asthma.

Let’s go over each of these reasons in depth.

1. You’ve Been Working Out Too Much

There is such thing as too much of a good thing.

If you’ve been pushing your body to the limit (or past its limit) every time you work out, eventually that’s going to take its toll on your stamina and on your energy levels.

Your body needs time to rest and recover after each workout. If you’re not giving it enough, you’ll feel it in the middle of your workouts – and fatigue will sap your strength.

more: What Causes Fatigue During Exercise?

Make sure to take at least 2 or 3 days during the week to rest after working out to make sure you stay at your physical peak.

2. You’re Not Drinking Enough Water

Your body loses a ton of moisture during a workout from the sweat and exertion.

And if you’re not replacing that water, it’s going to have a huge negative impact on your energy levels – leaving you feeling sluggish.

The reason behind it is due to your circulation – when your hydration levels drop your blood actually becomes thicker, making it harder for your heart to pump oxygen where your body needs it.

Make sure to stay hydrated before, during, and after a workout to keep at your peak.

more: What Causes Diabetes Fatigue And Can Diabetes Make You Tired?

3. You’re Not Getting The Nutrients You Need

This is a huge problem for people who are working out in order to lose weight.

Oftentimes, people who are working out and are on a diet in order to lose weight will limit their caloric intake too far – so that their body isn’t getting enough calories to keep it going.

Add in intense exercise on top of that and you have a recipe for exhaustion, fatigue, even collapse.

more: The Top 15 Reasons You’re Always Tired

If you’re trying to lose weight, make sure that you’re eating enough calories to keep yourself going and out of starvation mode. Only aim to create a 500 calorie deficit per day – anything more than that and you’re hurting your body more than you’re helping it.

4. You’re Not Getting Enough Quality Sleep

Your body needs sleep in order to rest, recover, and perform at its best.

Any disruption to your sleep cycle can mess up how you feel – and since sleep debt is cumulative, unless you rest and recover, you’re going to be feeling that sleep deficit for a while.

One of the best ways to make sure you’re getting good sleep is to try to go to bed and wake up at the same time each day – regardless of your responsibilities.

I know it’s difficult to give up sleeping in on the weekend – but if you can improve your sleep quality you can improve how you feel – and how much energy you have during workouts.

more: 9 Strange Reasons You’re Tired All The Time

5. You’re Not Getting Enough Iron

When your body doesn’t get enough iron, it creates a condition called anemia.

Anemia is a condition where your body isn’t producing enough red blood cells. Red blood cells are what carry oxygen from your lungs all over your body where it needs it.

When you don’t have enough red blood cells, your body becomes oxygen starved – and it results in symptoms like fatigue and exhaustion.

If you suspect you have anemia, talk to your doctor about fixing the condition. Don’t take iron supplements without first consulting with your doctor, as too much iron can be just as bad as too little iron.

more: 30 Scientifically Proven Ways To Boost Your Energy And Combat Fatigue

6. You’re Having Allergies

Is your workout fatigue especially hitting you in the spring? You might be suffering from allergies – which could be negatively impacting your exercise.

Your body needs oxygen in order to function – and it needs even more oxygen while you’re exerting yourself and working out. (That’s why as you work out harder, you breathe heavier.)

When you have allergies, it makes it hard to take in as much oxygen as you need during a workout – which could cause exhaustion and fatigue midway through.

7. You Run Out Of Glycogen

When your body stores energy from the food you eat – it stores it in different forms. The form we’re concerned with is glycogen – which is how your muscles and liver store energy from carbohydrates.

When you’re working out, your muscles turn to their stores of glycogen in order to get the energy needed to get through your workout.

Most of the time, there’s no problem. But if you’re working out for a long time (think longer than 60 minutes), your muscles can run out of glycogen – and when they do that, they have to turn to other sources of energy (which are much less efficient).

That means that you’ll feel more sluggish and exhausted – because your muscles have run out of their preferred energy source.

more: How To Tell If You’re Too Tired: Signs Of Chronic Fatigue

8. Your Thyroid Isn’t Functioning Correctly

Thyroid disorders are common – they affect many people and it often goes undiagnosed. Your thyroid is a gland in your neck about the size of a necktie that secretes hormones that control your metabolism, among other things.

Hypothyroidism – which is when the thyroid is underactive – can cause fatigue and exhaustion.

If you can’t figure out any other reason why you’re feeling drained and exhausted during a workout, it might be a good idea to talk to your doctor about the possibility of hypothyroidism.

more: How To Push Ahead When You’re Feeling Tired During A Workout

9. You Have An Infection

Your body needs to spend a ton of energy fighting off an infection so that it doesn’t get worse.

There are many infections that actually present without symptoms – so you might not even know you have an infection that’s sapping your strength and messing up your workouts.

utis and some gum infections are common infections that might not give you any other symptoms – so if you suspect you might have a utior another type of infection talk to your doctor. They can prescribe you antibiotics to take care of it, so that you can get back to peak shape.

more: 7 Things Draining Your Workout Energy

10. You Have Undiagnosed Heart Disease

This is one of the scariest possible reasons that you’re running out of energy.

Generally, heart disease will make you feel tired and fatigued all the time – even when you’re not working out and doing something as simple as going up the stairs.

The reason heart disease fatigues you is because it constricts your arteries, which means your heart has to work harder to pump blood and oxygen throughout your body, leading to fatigue.

more: Over-Exercising Or Burned Out: The Signs Of Workout Fatigue

If you suspect you might have heart disease, talk to your doctor immediately about how to handle it.