• Home
  • /
  • Blog
  • /
  • Why Do My Legs Feel Heavy When I Run?

Why Do My Legs Feel Heavy When I Run?

As an Amazon Associate we earn from qualifying purchases. Learn More.

If you’ve ever experienced heavy or achy legs while on a run, take solace in the fact that you’re not the only one feeling this way.

Why Do My Legs Feel Heavy When I Run

Most runners encounter this feeling at some point along their running journey. The trick to getting over this feeling is not letting it stop you!

Heavy legs that occur on a run, or weak legs after one may indicate that your training plan needs some changes.

However, after you implement a few of these switches, you’ll start feeling more confident and powerful after your runs again.

You’ll find out why legs can feel heavy while running in this article, as well as some of the things you can try to prevent heavy legs later on.

If you’re ready to stop heavy legs from affecting your running routine, keep reading!

Why Do My Legs Feel Heavy When I Run?

Heavy legs during running can occur for a variety of reasons, such as poor form, not drinking enough water, and overtraining.

We’ll cover some of the most common reasons for heavy legs while running below.

Overdoing Training

In most cases, heavy legs in runners are usually linked to their training plan. For instance, runners training for a long-distance session will cover several miles each week.

If you’re running too many miles than your body can handle, or not allowing enough time for your body to recover afterward, your legs can start to feel tired and heavy.

Bear in mind that overtraining might not just be down to the number of miles you run.

Moving too fast through a training plan, or jumping from one stage to another particularly a high one can all affect the way your legs feel.

If you’ve taken a break from running, or have been recovering from an injury, trying to get back into running too soon is also a sign of overdoing it.

Overtraining is serious, as it can lead to nasty injuries and illnesses. You might be tempted to progress as fast as possible, but try to resist at all costs!

Injuries will set you back more in the long run, so listen to your body.

If your legs are feeling particularly achy or tired, stop running for a few days, or lower the number of training sessions until your legs feel better.

Not Prioritizing Recovery

Why Do My Legs Feel Heavy When I Run

Recovery is essential, but many runners are guilty of skipping rest days. Not allowing your body enough recovery time is another common reason why heavy legs occur.

Skipping cool-down sessions after your runs, not taking rest days, or failing to carry out active recovery workouts can all have detrimental effects on your legs.

Improper Form

Poor running technique is another common reason why runners experience heavy legs.

Good form depends on how efficiently you run. It affects the way your foot strikes the ground, as well as your posture as you pound the pavement.

Improper running form, which involves your cadence, footstrike, and posture, can all add more stress to your joints. This added pressure can lead to your legs feeling achy and tired as you run.

Here is an overview of what elements correct running form involves:


Runners need to maintain correct posture while they run, as this prevents imbalances within the joints and muscles. Imbalances within these areas are one of the main causes of running injuries.


This is the way your foot strikes the floor as you run. There are three kinds of footstrikes that a runner can use: forefoot, mid-foot, and heel.

All three of these can be used on different landscapes and implemented in various ways.

Every runner will have their footstrike preferences, but in most cases, the mid-foot strike is viewed as a good middle ground.


Cadence involves the number of steps you take each minute of a run. The ideal running cadence is roughly 170 steps every minute.

Runners with lower cadence often have longer strides, which means that they overstride while running. This is when the foot lands too far in front of your form while you run.

Runners should avoid overstriding as it adds more stress to their leg muscles and joints.

Poor Sleep

Not getting enough sleep has health consequences which can all affect the way you run. Poor sleep is another reason why your legs might feel heavy after a run.

Research has shown that sleep is important for the maintenance of several bodily systems, including the skeletal, muscular, immune, and nervous systems.

Practically every bodily system is affected by poor sleep.

Most active individuals need to get between seven and nine hours of sleep every night. Attempting to run after only a few hours of sleep isn’t going to be good for your well-being.

Runners should prioritize getting enough sleep, but if your lifestyle limits the amount of sleep you can get at night, short naps in the afternoon may help you feel better.

Inadequate Nutrition

Why Do My Legs Feel Heavy When I Run?

Good nutrition is essential if you want to run regularly every week. Carbohydrates are very important for covering long distances, especially complex carbs that take longer to digest.

The body will transform the carbs you eat into glycogen. Once it does this, your muscles can then use glycogen as their energy source.

If you don’t consume enough carbs before a long run, your body won’t have the fuel needed to keep energized while you run.

If it doesn’t have enough energy, the body can start breaking down muscles for fuel. This can lead to the feeling of tired and achy legs.

Poor Blood Circulation

Poor blood circulation may be the reason why your legs feel tired during a run.

If your body cannot circulate enough blood to the muscles, it won’t receive the oxygen needed to transform into fuel.

Poor blood circulation often occurs when you’re training too hard, like attempting to run greater distances before your body is ready.

Not Drinking Enough Water

Proper hydration is essential for all types of exercise, no matter if it’s a short-strength workout in your bedroom or a long run outside.

The amount of water you’ll need varies depending on the type of exercise, but no matter what you do, the fluids you lose through sweat will need to be replaced.

Dehydration is linked with certain side effects, such as tiredness, muscle strains, and dry mouth.

If you aren’t drinking enough water, you may feel like the run takes more effort, or that your legs feel more fatigued than normal.

To solve this issue, listen to your body and drink enough water during the day to avoid feeling thirsty.

If you are running more than usual, you need to drink more water as your activity level increases. This is also the case if the weather becomes hot, as you’ll lose more sweat through the heat.

Iron Intake

If you often feel tired or experience heavy legs during a run, it’s a good idea to check your iron levels.

If you are iron deficient, your body will struggle to get enough oxygen to your muscles during a run, which can lead to heavy legs sensation.

Runners tend to consume enough iron from their diet alone, but there may be instances when your lifestyle struggles to reach the recommended intake.

Vegan and vegetarian diets, for instance, can often be lower in iron compared to meat-eating plans.

If you don’t eat meat, you need to prioritize eating pulses, dark leafy greens, and wholemeal bread. These foods contain lots of iron and are suitable for non-meat eaters.

You can also choose to take iron supplements in the form of a liquid or tablet. However, these are meant to supplement your diet, not be your sole iron source.

Supplements can be particularly useful for female runners, as women tend to have higher risks of iron deficiency, particularly those who experience heavy periods.

You can ask your doctor for a blood test to find out if you are deficient in iron.

How To Avoid Heavy Legs While Running

Why Do My Legs Feel Heavy When I Run

Now that we’ve covered some of the reasons why you might have heavy legs on a run, here are some tips that can help you avoid this sensation.

Proper Warm-Up

Warming up is essential to prepare your body for a run, both physically and mentally.

Effective warm-ups should consist of two parts, jogging, and dynamic stretching. These will help loosen your joints and muscles before your workout.

Proper Cool Down

As is the case with warming up, a proper cool down is important to lower your heart rate after a run.

Cool-downs are also important if you often experience stiff or tight muscles, as they will stretch out any of these areas that were used on your run.

Cool-down stretching, which is also called static stretching, involves holding a stretch at its end point for 20 to 45 seconds.

Aim to allow yourself 10 minutes at the end of every run to lower your heart rate and mobilize any muscles that were used during your run.

Your glutes, hamstrings, and quadriceps are all leg muscles that will work hard on your run.

This goes the same for your arms, back, and hips. Focus on stretching each muscle group during your cool down, as this can help ease any pain or stiffness later.

Foam Rolling

Foam rollers can be used to ease any stiff muscles, leading to less soreness during and after your run.

One of the main advantages of foam rolling is that it helps increase blood circulation to your muscles.

Looser muscles can help you perform better on your runs, particularly ones that cover longer distances.

If you often experience tight or heavy legs, you may want to try foam rolling during your warm-ups and cool-downs.

Wear Proper Shoes

Your usual trainers might be fine for light everyday use, but these won’t be supportive enough to help you on your run!

A proper pair of running shoes is essential for runners, especially those that run greater distances.

You need to make sure that your running shoes are designed to support your feet. They should also be flexible enough to move with your feet, and be strong enough to last a long time.

You can find a good pair of running shoes at specialty stores, but make sure that you try them on before you buy (Find out which running Nike Next Running shoe is better for you here).

The Bottom Line

Heavy legs while running is a common sensation among runners, but this could occur for any number of reasons.

Overtraining and improper recovery are the main reasons why you might feel this feeling during your runs.

You might want to progress as fast as possible, but if you don’t let your body catch up with you, you may end up doing more harm than good.

Other reasons why you might feel heavy legs during your runs are incorrect form, poor nutrition, not enough sleep, and dehydration.

Fortunately addressing these concerns is easy to do, so you may see a difference after making changes to your diet and wellbeing.

Heavy or tired legs could also be down to issues with the blood. Poor blood circulation and iron deficiency can lead to less oxygen reaching your muscles, leading to them feeling more tired overall.

If you do suspect that you may be iron deficient, contact your doctor for a medical assessment to be sure.

Other steps you can take are wearing the right training shoes, as well as warming up and cooling down before and after your workouts.

These steps may be simple, but they can go a long way in preventing heavy legs during your runs.

Related Posts