8 reasons why you feel your legs heavy when you run

It is normal to feel your legs heavy when you run, which is caused by the accumulation of lactic acid. 

However, if the legs are unusually heavy at the start of the run, it may be due to one of the following reasons.

It is normal to feel your legs heavy when you run, which is caused by the accumulation of lactic acid. 

Strength training is too intensive

The runner carries on the moderate strength training to have the benefit, can increase the muscle mass, enhances the running efficiency.

However, too much strength training, especially for the lower part of the body, can lead to extremely heavy legs during running.

In the offseason, runners can do more strength training. If there are more races, they can do it 1-2 times a week.

Neglect to stretch after running

After each run, the runner should spend 10 minutes stretching the body, not only to relax the body, but also to ease the stiffness and pain of the muscles, improve the range of movement of the joints, and reduce the possibility of stiff legs.


Overtraining means the body is stressed out of its comfort zone, making it impossible for the body to run in its normal state.

Signs of overtraining, in addition to heavy legs, include continued decline in performance, fatigue, mental fatigue, and headaches.

If the runner suspects that he or she has been overtrained, schedule a few days of rest immediately and consult a professional doctor if the symptoms have not subsided.

Shoe mistake

Heavy running shoes will increase the weight of the foot, which in turn will transfer the pressure to the legs.

Running shoes are too light, often can not provide adequate protection for the foot, the need for legs to bear more pressure, leading to premature fatigue of leg muscles, legs naturally feel heavy.

In addition, running shoes too old can also lead to a similar situation. A pair of running shoes can normally run 500-800 kilometers.

Incorrect form of running

If you run incorrectly, your body will experience additional stress, resulting in fatigue and heavy legs.

Running, the feet should not touch the ground for too long, and the feet should not lift the height too high, these two can not do, will consume more physical energy.

Weight gain

Even if you run every day, there is no guarantee that you won’t gain weight. If the diet is not controlled, the weight gain will be more obvious.

When running, the impact on your body is usually about five times your weight. So, every gain weight 1 catty, the body should bear tremendous pressure, both legs also can feel fatigue naturally.

Iron deficiency

Iron is part of hemoglobin and is used to produce red blood cells to carry oxygen to working muscles.

When there is not enough iron in the body, the muscles cannot get enough oxygen, which can quickly lead to a feeling of fatigue.

Vegetarians and female runners are the most vulnerable to iron deficiency and need to focus on iron supplements in their diet.

Water shortage

Running sweats can lead to the loss of water in the body, if not rehydrated in time, the blood will become sticky, the body has to consume more energy to ensure blood flow, running for the energy will be reduced, the legs will feel more heavy.

Spread the love


Hello, I am a website editor. I've edited more than 10 websites in the last five years. My hobbies are health, life and website technology. For me, writing an article is part of my life.All articles on the page are based on scientific confirmation, not individual speculation, and more source comments will be added in the future.Thank you for reading!

You may also like...

Leave a Reply

Your email address will not be published. Required fields are marked *