Why Do My Legs Feel Heavy When I Run? - Madaboutrun
A woman experiencing heavy legs while running

Why Do My Legs Feel Heavy When I Run?

Have you ever found yourself halfway through your morning run, only to be overcome by that heavy, weighted feeling in your legs? You know, the one that feels like you’re wearing bricks for shoes? Yeah, that one. 

If you’re well-acquainted with that dead-leg feeling, you’re not alone. In fact, that lagging, weighted feeling is more common than you might think. So, if your heavy legs keep popping out of nowhere to ruin your run, we’re here to help. 

Let’s take a look at why those dreaded heavy legs are so common and what you can do to stop them. 

A woman experiencing heavy legs while running

The Causes of Heavy Legs When Running

Ready to learn more about those notorious dead legs? Here are just a few reasons why your legs might be getting heavy during a run: 

The Wrong Footwear

Are your shoes weighing you down? Wearing the wrong shoes can make your legs feel heavy. If you’re a fan of stability shoes, you may have noticed this problem.

As great as they are, stability shoes are thicker and provide more support, so they tend to weigh more. Therefore, anything adding extra weight to your feet should be avoided when running. 

When looking for your next pair of running shoes, opt for something lightweight and supportive. There are still plenty of stability shoes that are strong and supportive without unnecessary weight. 

Remember: Lightweight shoes should never compromise on support. If your shoes aren’t supportive enough, you may experience the same problem. Inadequate support can put more stress on the body, causing muscle fatigue. 

Insufficient Fueling or Hydration

Are you hydrated and getting the right fuel before and after your run? Believe it or not, your diet and hydration levels can determine whether you get an episode of the dreaded dead leg. 

Before you go for a long run, you need to have enough of the right nutrients in your body. If you’re not getting enough of the right foods and you’re not adequately hydrated, your body will burn out quicker, and your legs are one of the first places you’ll start to feel it. 

Nutrient deficiencies can also cause issues with blood supply and circulation, leading to neuropathy or heavy legs. Here are a few vitamins and nutrients you should include in your diet: 

  • Vitamin B12
  • Iron
  • Zinc
  • Magnesium
  • Calcium
  • Vitamin C
  • Vitamin D
  • Vitamin E
  • Fiber 
  • Vitamin A 
  • Choline


If you’re overdoing it in the gym or when running, you may start to feel the strain in your legs. Putting excessive strain on your body can leave you more susceptible to illness, irritability, muscle and joint issues, headaches, fatigue and tiredness, mental fatigue, and more. If you’re running too fast or for too long, especially in marathons, exhaustion is inevitable. 

If you think this could be the reason why your legs are feeling heavy, here are a few things you can do: 

Ice Bath: If you can take the plunge, ice baths have been scientifically proven to reduce post-run pain in the legs. Ice baths can significantly reduce inflammation and suck that heavy-leg feeling straight out of your muscles. 

Enough Macronutrients: If you’ve overtrained and your muscles are feeling the strain, you need to focus on recovery. Getting enough micronutrients in your diet is imperative to aid the process. Ensure you’re getting a balanced mix of healthy fats, proteins, and carbohydrates with every meal, and steer clear from foods that encourage inflammation, such as refined sugars and processed foods. 

Foam Rollers: If you haven’t tried these yet, we’re here to tell you that you should! Foam rollers can help you stretch out the fascia around your muscles, improving blood flow, body temperature and increasing your range of motion. 

Poor Quality Sleep

Lack of sleep is the cause of many problems. These can manifest themselves as slow reaction times, lethargy, and poor memory in the short term. More serious issues can arise in the long term, such as diabetes, strokes, and heart issues. 

While you may be able to power through the day on just a few hours’ sleep, you won’t be helping yourself. Running after a bad night’s sleep can be even worse. When you’re overtired, your legs will become weaker and heavier, and your performance will decrease tenfold. Tiredness on the track will get you nowhere. 

  • If you’re struggling to sleep or need some tips and tricks to get on the right track, why not try some of the following: 
  • Avoid prolonged screen time before bed
  • Cut out alcohol and caffeine before you go to sleep
  • If you can’t manage a whole night of undisturbed sleep, try to nap

Low Iron Levels 

Low iron levels and other vitamin deficiencies can have detrimental impacts on your health. For example, a low iron level is also one of the most common causes of heavy legs or restless leg syndrome, a neurological condition that can cause heaviness and negatively impact performance. 

If you suspect you may be suffering from iron deficiency, talk to your doctor. You may need to take supplements and increase the amount of iron in your diet. 

Why Do My Legs Feel Heavy When I Run

Poor Running Form

We all know the importance of running form, but did you know that a poor running form can also cause heavy legs? Running with poor form can put extra strain on your body, and your ankles and legs can take the worst hit. 

To improve your running form, you’ll need to pay close attention to the following factors:

Contact time with the ground: Focus on lowering the amount of time your foot remains on the floor with each stride 

Vertical oscillation: Vertical oscillation simply means how high you bounce in the air with each step. To achieve the correct form, focus on lowering this height. Bouncing too high can waste energy and put more stress on your legs when you land. 

Although these are the leading causes of heavy legs, other issues can affect your form and make it harder to run. Some other causes of heavy legs and poor performance are: 

Running in the heat: Running in hot weather can cause you to overheat and overexert yourself quicker, putting more stress on your body and causing heavy legs. 

Chafing: Although chafing is often not the leading cause of heavy legs, it can make it harder to run if your legs are already fatigued. 

How to Prevent Chafing While Running

Wondering how to prevent chafing while running? Here are a few things you can try: 

  • Wear skin-tight layers
  • Stay hydrated 
  • Use anti-chafing powders or lotions
  • Choose moisture-wicking fabrics
  • Keep running accessories close to the body 

Final Thoughts 

Heavy legs are a problem faced by runners of all ages and abilities. Whether you’re a marathoner or a novice neighborhood runner, you’ll probably experience heavy legs at least once in your life. 

Although there are plenty of causes of heavy legs, there are also many things you can do to prevent and treat them. From improving your diet and sleep patterns to spending more time perfecting your running form, dead legs don’t have to get in the way of your life and keep you off the track forever! 

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