Why Do My Legs Feel Heavy When Running?

October 27, 2022

So you have gone for a run and noticed that your legs are feeling heavy. This, of course, will make carrying on quite tricky, and it can be frustrating and demotivating to carry on with your session.

But why exactly are your legs feeling heavy when you are running? Well, there are a few reasons why it might be happening. We will be looking at some of these reasons and how you can help stop them from happening in the future.

Have You Had Enough Carbs?

One of the biggest reasons your legs might be feeling heavy is that you haven’t had enough carbohydrates before starting your run.

You must fuel your body before you run. They give you the energy you need to work your muscles and help your recovery.

For example, if you’re on a low-carb diet, you might notice that your legs are getting heavy a lot quicker than if you were on a higher-carb diet. If you spend a lot of time running, you need to cater for your carbohydrate intake.

Check Your Running Form

Many people think all you need for running is motivation and your body. But you need to ensure you’re eating the right foods, gaining muscle and strength in the right areas of your body, and of course, you need a good running form.

Your running form is so important when running for longer periods and having a quick recovery period. Some people have a naturally good running form, but for most people, you must train yourself to have a good one.

Your running form will directly impact that heavy feeling in your legs, and if you have good form, you can stop that heavy feeling from coming on.

Some of the best things you should do to improve your running form include keeping your shoulders relaxed, keeping your core engaged, avoiding crossing your arms in front of your body, and avoiding hunching over the top half.

Be Careful Of Overtraining

Some people love pushing themselves and their bodies to the limits, which is fine, but you definitely need to give yourself a break once in a while.

You may not know this, but your joints and bones gain their strength much slower than your cardio fitness, so you have to compensate for that. Just because you might be able to train for longer and not get tired, that doesn’t mean that your body isn’t being overworked.

You need to take a break immediately if you feel any pains, aches, or heavy feelings in your legs. If you are overtraining, you can cause serious injury if you don’t allow your body to rest.

Check Your Iron Levels

Iron deficiency can cause a lot of problems if left unmanaged. When your body isn’t getting enough iron, it can cause issues and problems transporting enough oxygen to your muscles, especially when running and training.

This will cause a lot of fatigue and cause your legs to feel heavy when you run.

If you are concerned about your iron levels and think this might be why your legs are feeling heavy when you run, it’s in your best interest to get tested by a doctor and see if they can offer any treatments to help you manage your iron deficiency.

One of the best things you can do to improve your iron levels adds more iron-rich foods to your diet.

Some of the best foods include beef, lentils, dark chocolate, tofu, crab, and white beans. You can also take iron supplements, usually purchased in pharmacies over the counter.

Are You Wearing Heavy Shoes?

If you’ve checked all of the other things on this list and don’t think they cause your heavy legs, have you checked the shoes you use to run?

You might not have even considered that your shoes are too heavy, and that’s ok! It’s not something that you’d usually need to think about.

If you’ve recently swapped over to some new shoes, this is a big cause as to why your legs might feel heavy when running. We know it sounds silly, but you’d be surprised at how your shoes impact your running experience.

It’s in your best interest to go to a store specialising in running shoes and get some advice from the people who work there to help you pick out a pair of running shoes that will enhance your performance.

If you want to run longer without getting that heavy feeling in your legs, seek the right advice for the best shoes.

Have You Had Enough Water Today?

Many people ignore how seriously dehydration can impact your body and performance in anything, let alone just running. It can cause headaches, irritability, joint pain, and much more.

If you are dehydrated while running, your body will automatically start to shut down and feel fatigued. Until you rehydrate, you likely won’t feel any better.

If you are too dehydrated, your muscles can seize up and cramp, which will definitely cause your legs to feel heavy when you run. Make sure you drink enough water before you go on a run, and keep a decently sized bottle of water on you while you’re running.

Keeping yourself hydrated might be the only thing you need to keep yourself running for longer.


It is important to listen to your body in anything you do, including running.

When your legs are feeling heavy, you can remedy it yourself by checking to see if any of the things in this article are causing it.

Dead Legs When Running

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