Why are you more likely to get cramps when running in the summer than in other seasons?

Cram, also known as muscle spasm, is a spontaneous forced contraction of muscles. Cramps during running are mostly caused by overuse of muscles, and muscle fatigue leads to abnormal neuromuscular control. There are many causes of muscle fatigue, but some factors in summer make it easy to get cramps.

1. Overheating in the body will inhibit heart function and muscle contraction to a certain extent

During exercise in a hot environment, in order to dissipate heat, the blood vessels on the body surface will expand greatly, and the skin blood flow will increase and flow through the muscles. The blood flow is relatively reduced, and the amount of blood returned to the heart is reduced, which will lead to a significant increase in heart rate and a decrease in muscle contraction ability. All organs and metabolic systems of the human body, such as perspiration, respiration, blood circulation, and nerve cell function, will be affected, making it easy for neuromuscular control abnormalities and spasms to occur.

2. The body sweats a lot and loses water and electrolytes

The biggest challenges of summer running are temperature, humidity and sunlight exposure. When the weather gets hot, sweating becomes the main way to dissipate heat. Nerve and muscle excitation is conducted by generating action potentials based on changes in ion concentration inside and outside the cells. With heavy sweating, electrolytes are lost, and muscles need to work harder to stay excited, making them more likely to fatigue and reduce their tolerance to exercise intensity. When fatigue reaches a certain level and disorders occur, cramps are likely to occur.

3. Lactic acid accumulation and glycogen depletion

Running in high temperatures in summer will increase your heart rate and increase your body’s energy consumption. When exercising in a hot environment, the body relies more on anaerobic metabolism. Since the raw material for anaerobic metabolism is only sugar, the glycogen stored in the body is consumed faster than in other seasons, and the lactic acid produced by anaerobic metabolism will also increase. Lactic acid accumulation and glycogen depletion both exacerbate muscle fatigue and increase the chance of cramps.