6 simple ways to prevent heavy legs when running

  • Post last modified:October 24, 2020
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Tired, achy and heavy legs when running is a discomfort that discourages many runners from going for a run. If you’ve ever felt like your legs are tonne weights, then you’re not alone.

The truth is many runners suffer from heavy leg syndrome at one time or another. The secret is not to let it put you off running for good!

But what causes heavy legs when running? Dehydration, iron deficiency and overtraining have all been attributed to sore and heavy legs.

If heavy legs is something you experience on a regular basis, then it could be a sign that you need to reassess your training routine.

In this blog, I’d like to explain some common causes for heavy legs when running and suggest some simple fixes so you can get back to running in no time.

heavy legs when running

Cool down after each run

Many runners have a love-hate relationship with the cool down. 

Cool down stretching (also known as static stretching), when combined with other things like foam rolling, can do you a world of good.

This is especially true if you regularly suffer from tight or stiff muscles or muscle soreness.

The secret is to focus on static stretches, instead of dynamic stretches, after a run. This is when you hold the stretch to the end of its range of motion for roughly 20 to 45 seconds. 

Try and give yourself 10 minutes at the end of each run to bring your heart rate down and stretch parts of your body involved in running. 

Your quadriceps, hamstrings, glutes, hips, back and arms are all utilised when running. Make sure you target each muscle group to help alleviate any soreness or pain. 

Check out my post on the best cool down stretches to do after a run for more tips and advice.

Avoid overtraining

Overtraining can creep up on any runner so matter their running experience. 

There comes a point in a runner’s life when they become so consumed by running that it’s easy to forget how many miles they’re actually doing each week.

If you’re training for a half marathon, marathon or even an ultra-marathon, then it can often be all too tempting to go for a run every day.

Whilst this may sound sensible to get yourself physically and mentally prepared for the race, you could end up putting too much stress on your body. 

Overtraining is not always linked to a high volume of mileage in your training plan. It can also be linked to training plans that progress too rapidly, large jumps in training plans or trying to do too much too soon after an injury or break in running. 

More often than not, overtraining can lead to illness and injury, so don’t be tempted to power through it. 

Instead, take a step back for a few days and reduce your overall training until you start to feel better again.

Check out my blog on how to start running after a long break for more tips on getting back into running.

heavy legs when running

Improve your running form

I’ve spoken many times about proper running form on my blog. This is because I think it’s incredibly important when running, but unfortunately many runners fail to see the benefits of good running form.

If you’re a new runner, you may struggle to know what good running form looks like. If so, then I suggest you check out my four top tips on how to improve your running form

The truth is, poor running form, especially when it comes to your stride and cadence, puts extra stress on your body which can in turn cause tired and heavy legs.

The amount of time your foot stays on the ground with each stride can have a big impact on your form. Likewise, how high in the air you bounce with each step can create more stress when you land. 

As a general rule of thumb, try and take quick steps to help propel you forward and try not to bounce too much when you run. 

By doing so, you will reduce stress on your legs and improve your pace overall. 

Drink enough water

Hydration is critical to any form of exercise, whether it be a long run or a quick HIIT workout in your living room.

Of course, the levels of hydration required differ with each form of exercise, but the end goal is always the same: to replace fluids lost through sweat.

Dehydration, or not drinking enough water, is associated with muscle cramps, fatigue and a dry mouth. 

If you’re dehydrated, you might feel like your legs are more tired than usual or the run just feels harder. 

To combat this, tune into your body and drink enough fluids throughout the day so you don’t feel thirsty. 

If you’re exercising more than normal, then it’s important you adjust hydration according to your activity levels. The weather may also mean you need more fluids on those hot runs. 

Check out my post on what to eat before a run for more tips on what to eat and drink before a run.

heavy legs when running

Get enough sleep

Lack of sleep is linked to many conditions that can impact your running performance, including tired and heavy legs when running.

A 2014 study on the relationship between sleep and exercise concluded that sufficient sleep is essential for the restoration of nervous, immune, skeletal and muscular systems. Adding that virtually all bodily systems are impacted by poor or inadequate sleep.

Most athletes need between seven to nine hours of sleep each night. Trying to power through a run with just a few hours of sleep is probably not a good idea.

Make a good night’s sleep your priority. If your lifestyle means you can’t get at least seven hours of sleep at night, short afternoon naps may help training feel easier and improve performance.

Check your iron levels

If you regularly experience tiredness, fatigue and heavy legs when running, then it’s worth checking your iron levels.

Iron deficiency means your body has a more difficult time supplying oxygen to your muscles on a run, which can result in a heavy leg feeling.

Most runners get enough iron in their diet, however there are times when your eating habits may mean it’s more challenging to get the recommended intake. 

With a vegetarian or vegan diet, it’s important you eat a variety of iron-rich foods such as dark leafy vegetables, pulses and wholemeal bread to maintain your iron levels. 

Iron supplements in the form of a daily tablet are also an option but shouldn’t be your only source of iron. 

If you’re a female runner, then your period may mean you’re at a greater risk of iron deficiency, especially if you suffer from heavy menstrual bleeding. 

A quick blood test with your GP will help you identify if you’re suffering from iron deficiency. 


Caroline Geoghegan

Caroline Geoghegan (aka Run With Caroline) helps people become faster and stronger runners. She started her blog in 2018 to share her passion for running. Caroline is a UK Athletics qualified Run Leader and Run Coach and NASM qualified Personal Trainer.

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