A non-obvious way to prevent depression has been named

Scientists from University College London have reached an unexpected conclusion: it is muscular strength, rather than endurance, that may play a key role in protecting against depression. The study was published in the Journal of Affective Disorders (JAD).

Physical activity has long been considered a factor that reduces the risk of depression, yet the mechanisms behind this effect have remained not fully understood. The researchers decided to separate two components — cardiorespiratory endurance and muscular strength — and determine which one is truly associated with mental health.

The study used data from more than 340,000 individuals from the UK Biobank database. To establish causal relationships, the scientists employed the method of Mendelian randomization, which allows the assessment of factors' influence through genetic characteristics while minimizing the impact of lifestyle.

As a measure of strength, the researchers used hand grip strength — a widely used and reliable marker of overall muscular strength. Mental health status was assessed through diagnoses and questionnaires, including key symptoms of depression: low mood, loss of interest in life, concentration problems, and changes in appetite.

The results were unexpected. No association between endurance and depression was found. However, muscular strength demonstrated a consistent protective effect.

Specifically, an increase in grip strength of 0.1 kg per kilogram of body weight reduced the risk of depression by approximately 14%. Stronger participants also experienced individual symptoms less frequently: the likelihood of anhedonia — the loss of pleasure — decreased by 21%, and appetite disturbances by 44%.

Interestingly, the effect was more pronounced in women. In women, strength was associated with a reduction in symptoms such as depressed mood, loss of interest, and concentration problems. In men, this association was less evident.

Why muscles affect mental health is not yet fully clear. One hypothesis is related to everyday activity: reduced strength impairs the ability to cope with daily tasks, which may intensify feelings of helplessness and contribute to depression. Another hypothesis is biological: when muscles contract, they release proteins that may potentially have a protective effect on the brain.