Excessive exercise can actually damage the liver! Research finds that excessive exercise increases the risk of liver fibrosis

In today's society, exercise has become an important way for many people to pursue a healthy life. From running, fitness to various extreme sports, people use exercise to strengthen their physical fitness and improve their quality of life. However, as the ancients said, "everything will turn into its opposite when it reaches its extreme", and the same is true for exercise. Excessive exercise, a phenomenon that has gradually attracted attention in recent years, what kind of impact will it have on our bodies?

Past studies have mostly focused on the benefits of exercise to the body, and relatively few studies have focused on the potential harms of excessive exercise. The liver is an important detoxification and metabolic organ in the human body, and its health directly affects the overall health of the human body. Recently, a research team led by Huang Yan, Peng Hui and Lu Renbin from Xiangya Hospital of Central South University published an important study in the famous journal Cell Metabolism, revealing the adverse effects of excessive exercise on the human body and the potential mechanisms behind it.

Research Process

In order to comprehensively and deeply explore the impact of excessive exercise on the liver, the research team adopted a variety of research methods, including big data analysis, clinical trials and animal model research.

The research team first extracted data from 1,255 subjects from the National Health and Nutrition Survey cohort in the United States. These data included the subjects' physical exercise status, liver-related indicators, etc. By analyzing these data, the researchers tried to find the correlation between total exercise and liver health status.

To further verify the results of the big data analysis, the research team recruited 28 Chinese subjects aged 18 to 40 with a BMI of 18.5 to 23.9. These subjects were evenly divided into an overtraining group and a non-overtraining group. After a period of training, the researchers compared the liver-related indicators of the two groups of subjects to observe whether excessive exercise would cause liver damage.

In order to further explore the molecular mechanism of excessive exercise leading to liver damage, the research team used a mouse model. The mice were divided into three groups: a control group that did not exercise much, a moderate-intensity exercise group, and an excessive-exercise group. By comparing the liver-related indicators of these three groups of mice, the researchers tried to find out the specific mechanism of excessive exercise leading to liver damage.

Research Findings

Clinical experimental results show that there is a "J"-shaped correlation between total exercise and liver health. When the total weekly metabolic equivalent reaches 2198.744, the risk of liver fibrosis reaches the lowest point; as the total metabolic equivalent increases, the risk of liver fibrosis gradually increases. This shows that moderate exercise is good for liver health, but excessive exercise may have adverse effects on the liver.

The results of clinical experiments showed that after the training, the subjects in the overtraining group had increased levels of alanine aminotransferase and aspartate aminotransferase. These two enzymes are mainly present in liver cells. When the liver is damaged, these enzymes will be released into the blood, causing their levels to increase. At the same time, liver fibrosis markers were higher and liver stiffness was also increased. These results show that excessive exercise does increase the risk of liver fibrosis.

Animal model studies further confirmed the results of clinical trials. In mice that over-exercised, alanine aminotransferase and aspartate aminotransferase levels increased, collagen deposition occurred in the liver, hepatocyte apoptosis was enhanced, and the expression of pro-necrosis genes and pro-inflammatory genes was higher. These results indicate that excessive exercise can indeed cause damage to the liver.

Further research found that excessive exercise leads to a large accumulation of lactic acid in muscles, prompting the muscles to release extracellular vesicles called "lactate bodies". These lactate bodies enter the liver through blood circulation, induce apoptosis of hepatocytes and activation of hepatic stellate cells, and eventually lead to liver fibrosis.

It is worth noting that the researchers found that salidroside, the active ingredient in the traditional Chinese medicine Rhodiola rosea, can effectively inhibit the formation of lactic acid bodies, thereby preventing excessive exercise-induced liver fibrosis.

Exercise Tips

1. Moderate exercise: Exercise is the source of health, but it should follow the principle of moderation. It is recommended to formulate a reasonable exercise plan based on personal physical condition and exercise ability, and avoid excessive exercise.

2. Pay attention to liver health: Check liver-related indicators regularly, especially for people who do high-intensity exercise for a long time. If any abnormality is found, the exercise plan should be adjusted in time and medical help should be sought.

3. Reasonable use of supplements: For people who engage in high-intensity exercise for a long time, they can consider the reasonable use of supplements such as salidroside under the guidance of a doctor to prevent liver damage.

As an important way for humans to pursue a healthy life, exercise has its own benefits. However, excessive exercise may damage the liver and even induce liver fibrosis. This discovery reminds us that more exercise is not always better, and moderation is the key. Liver damage caused by excessive exercise is not only a warning to personal health, but also a reflection on the concept of exercise. It tells us that health is not a simple accumulation of quantity, but a qualitative improvement. We need to understand exercise more scientifically and regard it as a healthy attitude towards life.

References: Liu Y, Zhou R, Guo Y, et al. Muscle-derived small extracellular vesicles induce liver fibrosis during overtraining. Cell Metab (2025).