Legs Feel Heavy While Running? Top 9 Causes + How to Fix It

If you’re wondering why your legs feel heavy when running, then you’re in the right place.

There can be many different causes for that heavy legs sensation, and they might not be so obvious at first.

But don’t worry, in this article, you’ll not only learn the 9 causes for feeling like your legs are feeling heavy when running, but also the 10 ways you can prevent and fix it. We’ll also discuss when it’s time to head to the doctor.

Why Are My Legs Heavy When Running?

It can be very frustrating to have tired legs when you’re just starting out as a runner or putting in a lot of miles to train for a big race.

Heavy leg days may simply be an inevitable price for training. You’re growing stronger and building up your leg muscles, but your legs are continually recovering from the training load.

The heavy leg sensation usually develops during your most intense training weeks and fades away following a rest day.

It’s the persistently heavy legs that cause problems. When you never seem to recover from one day to the next and your legs are always heavy and fatigued after a run.

This is the time to investigate the causes of heavy legs during jogging. When you find the cause, it’s usually an easy fix.

What Causes Heavy Legs When Running?

There are many possible causes of leg fatigue, and not all of them are obvious. For example, we know that if you did heavy strength training for lower body on Monday it could very well mean that Tuesday’s run feels a little slower with a heavy feeling as your muscles are still trying to recover.

But when it’s less obvious, we need to look at everything you do before or after a run.

When it comes to running, everything from your food to your fueling methods has an effect on how your legs feel.

Let’s look at the top possible causes of why your legs feel heavy when running:

1. Overtraining

If you frequently experience heavy legs, it could indicate that you are overtraining.

When you overtrain, you place excessive physical stress on your body. It can be caused by a training plan with too much overall volume, mileage that increases too quick, or trying to do too much too soon after an injury or break.

Overtraining is also more likely to be the cause of tired legs when running if you are a beginner runner or are just getting started.

Generic training plans are simply guidelines. You must modify them to meet your requirements, and if possible, with the help of a running coach.

It may be necessary to take extra rest days or repeat a week before going on to a more difficult training if your plan leaves you with frequent dead legs and you find that you’re just not recovering properly.

Overtraining symptoms include decreased performance, overall fatigue and tiredness, mental exhaustion, headaches, irritability, and a higher rate of injuries.

If you’re experiencing these symptoms, it’s a good idea to see a doctor first to rule out any other underlying medical conditions.

If these symptoms are caused by overtraining, try resting for a few days followed by a few weeks of reduced training volume.

Get the rest your body requires instead of trying to push through overtraining, which can cause lasting issues.

2. Wearing the Wrong Shoes

It may come as a surprise, but the wrong shoes can also make your legs feel heavy. You want running shoes that are light, but still provide the support you need.

Stability shoes for overpronation, for example, tend to be heavier since they’re thicker and provide more support.

If they’re the right level of support for you, you’ll feel fine, but if they’re too heavy it can lead to the sensation of having heavy legs when running.

On the other hand, having a shoe that is too light and not supportive enough might also cause issues.

If you don’t have enough support in your shoe, your body may be under extra stress as your foot meets the ground. This can make the muscles get tired faster.

This can also happen with worn-out or old shoes.

How to choose the right right running shoe >>

3. Poor Running Form

Running with bad form frequently puts extra strain on your body and might result in tired, heavy legs.

Poor running form causes your body to use energy inefficiently, which not only slows you down but also causes you to tire out more quickly, increasing the likelihood that your legs will feel heavy.

And so, maintaining a good running form when running can prevent you from fatiguing too quickly and minimize the risk of experiencing heavy legs when running.

4. Poor Diet

A insufficient diet with a lack of carbohydrates (and total calories) can also make you feel like your legs are heavy while running.

When you run, your body constantly uses a combination of carbohydrates and fat to provide the energy your muscles require. These carbs are stored in your muscles as glycogen.

If you drastically reduce your carb intake at meals, your body will be unable to store as much glycogen in your muscles. This makes it harder for your body to make energy while you run, which can make you feel like you have ‘dead legs.’

A well-balanced meal plan that incorporates healthy carbohydrate sources is the best option for most runners. Try including more fruits, veggies, and whole grains in your meals and snacks to see if your runs improve. It’s incredibly important for all runners to get enough carbs.

Figure out how many calories runners need to ensure you aren’t underfueling and hindering your progress.

5. Iron Deficiency

Iron is a component of hemoglobin, which carries oxygen to your muscles.

When your body doesn’t get enough iron, it can have trouble transporting the right amount of oxygen to your muscles during a run.

When this happens, you will most likely feel fatigued and exhausted, but some people may also have a heavy leg sensation.

Most athletes get enough iron in their diet by following a well-balanced diet. However, two kinds of runners may find it more difficult to achieve their iron requirements.

The first category includes vegans. It’s not difficult to meet iron needs as a vegan but it does take some effort. Include a variety of iron-rich plant-based foods, as well as a good source of vitamin C, to aid iron absorption.

The second category is female runners. Female runners may be more susceptible to iron deficiency since they lose iron each month during their periods.

Talk to your doctor if you feel tired all over and your legs feel heavy when you run.

If your doctor discovers that you have iron deficiency anemia with a simple blood test, he or she recommend a treatment plan.

This might be as simple as including more iron-rich foods into your diet or taking a daily iron supplement until your levels return to normal. Absolutely DO NOT supplement without blood testing.

Learn more about iron deficiency in runners >>

6. Dehydration

Dehydration can lead to muscle cramping, but it can also cause fatigue during a run. Like iron deficiency, this fatigue can make runners feel like they have heavy legs.

Staying hydrated is incredibly important during runs. If you sweat out a lot of water and don’t drink enough to make up for it, your blood can get thicker. To pump this blood, your body has to work harder.

The run may seem harder or your legs may feel more tired out than usual.

So make sure to prevent hydration by learning all the ways you can hydrate yourself as a runner. This usually means using electrolytes while training.

7. Lack of Sleep

While you may be able to get through the day on only a few hours of sleep, you’re most likely not doing your body any favors. Lack of sleep can make your legs feel tired and worn out when running

Most athletes need to sleep between seven and nine hours every night. And while some might need more or less than others, it’s important to get the right amount of rest and sleep as this can definitely result in heavy legs feeling when running.

8. Insufficient Recovery

Runners who consistently skip cooldowns, avoid easy runs, and rarely schedule rest days are more susceptible to heavy legs when running.

Apart from sleep, make sure you’re getting the right number of rest days when training and give your body the time it needs to recover after hard days.

Some coaches like to say there is no such thing as overtraining, just poor recovery.

9. Poor Blood Circulation

Heavy legs may also be a result of poor circulation, particularly a condition known as chronic venous insufficiency. In a healthy body, veins return blood to the heart from the lower extremities.

When moving, the legs contract to help this process defy gravity. Additionally, the veins have tiny valves that stop blood from flowing back down.

However, in chronic venous insufficiency, these valves don’t function properly. Blood can flow back down and pool in the legs. This results in swollen, heavy legs.

Exercise helps prevent this condition, so if you’re a runner you shouldn’t have this issue but it’s important to mention this one so you can get checked by your doctor just in case.

10 Ways to Prevent Heavy Legs When Running

Now you know the reasons why your legs feel heavy when running, it’s important to look at the 10 ways you can help prevent them when running.

Most of them are easy fixes. Let’s look at each of them one by one:

1. Pay Special Attention to Recovery

Recovery is just as important as training.

Constantly overloading your body with hard training days with no rest is the easiest way to have heavy legs and ultimately get injured.

So, don’t skip those rest days and pay extra attention to recovery in the form of massages, foam rolling, etc.

2. Avoid Overtraining

Training for a marathon can be exciting, but it’s easy to fall into the trap of overtraining.

Try to be reasonable with your training.

Running with heavy legs can be a warning sign. At the peak of your training schedule, it may be acceptable to continue running on tired legs.

However, persistently heavy legs are a red flag. Listen to your body and reduce your training. Less is sometimes more.

Checkout all the signs of Overtraining to see if they fit you >>

3. Work on Your Running Form

Your running form affects you every day when you go out for a run. It includes everything from your posture to your cadence to your foot strike.

Over time, a bad running form can result in many problems and conditions, including the feeling of heavy legs when running.

• Work on your range of motion with hip mobility
• Continue focusing on a good stride that lands under your body
• Include hips, glutes and core workouts weekly – this is going to ensure you can maintain good form

Improvements in these areas will naturally result in better running form and will have a greater impact on avoiding heavy legs while running.

4. Don’t Forget to Warm Up

Warm up those muscles before putting them to work, especially if your job requires sitting at a desk all day!

Taking out time for dynamic stretching before you start running is incredibly important. Warm up your muscles and increase your range of motion with dynamic stretches.

Consider it as getting your body ready to run. 5 to 10 minutes of stretching can make all the difference in lubricating your joints, getting your heart ready to go and preventing muscle strains.

5. Stay Hydrated

As we learned earlier, dehydration, or not drinking enough water, will have an impact on your performance, such as making your legs feel heavy when running.

Runners must consider more than just fluids. Water and electrolytes are depleted during exercise. If you’re training hard or in hot weather, using hydration mixes during recovery, as well as before and during your runs, can be beneficial.

Make an effort to pay attention to the cues that your body gives you and drink when you feel thirsty.

6. Get the Right Amount of Sleep

Sleep deprivation will not only impair your performance but will also make running feel more difficult. So, maintain a regular sleep schedule if you want to feel better while running.

Adults require 7 to 8 hours of sleep per night, while teenagers may require up to ten.

Getting enough sleep is frequently neglected, but it can contribute to the sensation of having heavy legs when running.

7. Get a New Pair of Running Shoes

Running with heavy legs could simply be due to the midsole foam on your favorite running shoes wearing out. That’s why you’re supposed to change your running shoes every 500 miles or even lesser from some brands.

Keep an eye out for uneven wear on the soles of your running shoes. It could be an indication that you require new shoes with better foot support. If that’s the case, change your shoes and see if that helps fix the heavy legs feeling.

Additional tips to know when to replace your running shoes >>

8. Fuel Up

If you’re getting the heavy legs feeling midway through your run, chances are that you’re not fueling properly both before and during your workouts.

Make sure to carry energy gels and chews on long runs where you might deplete your glycogen stores. Learning how to fuel up can make the difference between having heavy legs or not having heavy legs when running.

9. Don’t Ignore Your Diet

Speaking of fueling up, it’s important to do that not just when you run, but to also focus on your diet overall.

Diet is an important part of any runner’s performance and can be a cause of heavy legs when running.

A low-carb diet or vitamin deficiency can cause of ripple effect and end up leaving you lethargic.

So, it’s important to have the right type of runner’s diet that can help you recover from long runs and give your body what it needs to stay healthy.

10. Get Your Iron Levels Checked

Iron deficiency is more common than you might think among runners. Low iron levels can make your legs feel heavy when running.

Runners lose iron through foot strike as red blood cells are damaged when their feet strike the ground, lowering their hemoglobin levels. Female runners also lose iron during periods.

If you feel you’re deficient in iron, rather than just taking iron supplements, it is best to consult with your doctor.

Most people’s bodies will adjust to iron overload by absorbing less iron from their food. Plus, high iron levels can cause long-term health problems in a few cases.

When Is It Time to Go to a Doctor

If you’ve ruled out the more obvious causes of heavy legs while running, it’s time to consult your doctor about iron levels and blood circulation.

Heavy legs while running could be a symptom of more serious underlying health issues. If you’ve tried everything on this list and still haven’t found a solution, it’s time to seek medical help.

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