Do your legs feel heavy when you run? Here is why and how to remedy it

On occasion, whether you're a runner just starting out or a seasoned marathon runner, you may have noticed that nagging feeling of heavy legs during your runs. But what causes this feeling and how can we overcome it? We unravel the mystery of "heavy legs" and offer you some science-based tips to keep your legs light and ready for action.

Understanding the heavy legs phenomenon

Running is an intense physical activity that tests our muscular and cardiovascular endurance. During a training run, especially if we are faced with a long run or a quality session (series, changes of pace), our muscles work hard and burn energy. Fatigue, lactic acid accumulation, dehydration and electrolyte loss are the factors that can contribute to the feeling of heaviness in the legs.

Fatigue and muscle stiffness

Muscle fatigue can be a major factor behind heavy legs. When we run, we consume glycogen, which is the main way our bodies store carbohydrates for energy. If we deplete our glycogen stores during an intense or prolonged run, our muscles can become tired and feel heavy. In addition, some studies have found that fatigue can reduce the tension of our legs, which can decrease our running efficiency.

Hydration is essential

Dehydration and loss of electrolytes such as sodium and potassium can be other culprits of heavy legs. These electrolytes are essential for muscle function, and their loss can cause weakness and heaviness in the legs. That's why it's important to stay hydrated before, during and after your run.

How to relieve heavy legs

Now that we know the causes, what can we do to relieve and prevent heavy legs? Here are some tips:

1. Warm up properly: Before you start running, it's important to prepare your muscles with a good warm-up. A gentle jog or a brisk walk for five to ten minutes can help activate your muscles.

2. Listen to your body: If your legs feel heavy during a run, it may be time to slow down. This may be a sign that you are pushing too hard.

3. Increase your cadence: If you can't increase your speed, try increasing the number of steps you take per minute. Even if you don't go faster, you will be optimising your running.

4. Stay hydrated: Always carry a bottle of water with you during your runs, and consider carrying an isotonic drink for longer or more intense runs.

Feeling heavy legs during a run can be frustrating, but with these science-based tips, you can keep your legs light and ready to go. Remember, listen to your body and take the right steps to take care of it. Prevention and proper management can help you maintain a steady pace and enjoy your runs, regardless of the distance.