Why Do My Legs Feel Heavy While Running?

Why Do My Legs Feel Heavy While Running?

Why do my legs feel heavy while running?

A common question and something almost every runner has gone through at some point. One day, you feel great…then the next, you don’t. Why? Why does a usually easy pace feel so hard?

There are so many reasons your legs might feel heavy when running. Some are more serious than others. Some might even surprise you.

Why Do My Legs Feel Heavy While Running?

Why do my legs feel heavy while running?

Weight Training:

We know weights and strength exercises are good for runners. It’s one of the best ways to stay healthier and more injury-free. But, weights also affect how our legs will feel. Do your heavy leg workouts on the same days you do your intense speed sessions. Keep your hard days hard and easy days easy. You might be super sore the next day, but you’ll know why.


The answer to why does my legs feel heavy while running is most commonly overtraining. Running is fun, and it can easy to want to do more and more and more. But overtraining will set you up for burnout and injury. If your legs feel heavy for several days in a row, take time off. It’s ok, and you won’t lose fitness.

Incorrect Fueling:

Probably the second most common answer to why my legs feel heavy while running is not enough fuel. Fuel is what makes you able to withstand hard paces. Your body needs carbohydrates and they are imperative to your training. When your energy runs out, your body turns carbohydrates into fuel and more endurance. If you haven’t consumed enough carbohydrates and fuel, your body can’t convert them into energy.

Vitamin Deficiency: 

Just as important, but vitamin deficiencies are another season your legs will feel heavy. Prevalent in women, lack of iron is another reason your legs feel heavy while running. Iron helps to pump blood into the muscles, which is then used for energy. Vitamin deficiencies are one of the more serious reasons your legs might feel heavy. If you suspect this might be the case, don’t just supplement and see your doctor get blood work done.


If you’ve read this blog the last few months, you know that dehydration has quickly become a topic of conversation with me. Water and electrolytes are essential to run your best. Dehydration can also play a role in why your legs feel heavy while running. Instead of waiting until you “feel thirsty,” drink throughout the day, during your run, and after your run too.

Lack of Sleep:

One of the easiest ways to improve your running is to sleep more. That’s it. Nothing else fancy. Getting more sleep will promote recovery, which will also help your legs feel better.

Worn out or the Wrong Shoes:

Sometimes the wrong shoes will make all of the difference. Yes, really. Not every shoe is right for everyone, and sometimes your issue is as simple as the wrong shoes or worn-out shoes. Shoes have a life cycle, and not replacing them often enough can lead to legs feeling heavy or injury. In fact, one of the first signs to tell your shoes have reached their limit is your legs feeling heavy. You can read more about running shoes in my ebook.

Running is supposed to be fun, and nothing is fun when it feels tough or your legs feel tired. It’s important to measure trends. If your legs feel tired for a day or two, that might be because of a hard workout, but if your legs are consistently tired and feel heavy, something else could be going on.

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Question for you: How do you deal with heavy legs?

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