Building muscle might do more than improve physical health — it could also help protect against depression. A study published in the Journal of Affective Disorders has found that adults with stronger grip strength and greater muscle mass were less likely to experience depression. The findings suggest that targeting muscle development through exercise may be an effective strategy to improve mental health.
Depression is a widespread mental health condition that affects millions of people worldwide, characterized by persistent sadness, reduced energy, and difficulty finding pleasure in previously enjoyable activities. It is a leading cause of disability and places a significant burden on individuals, families, and healthcare systems. Despite advancements in treatments like therapy and medication, many patients experience recurrent episodes, underscoring the need for better preventive strategies.
Muscle mass and strength are known to decline with age and can also be affected by lifestyle factors such as diet and physical activity. While previous studies have suggested a potential connection between muscle health and depression, the results have been inconsistent, possibly due to differences in study design and measurement methods. The new study, led by Linjie Qiu of the China Academy of Chinese Medical Sciences, aimed to clarify this relationship by analyzing a large, nationally representative dataset from the United States.
The researchers analyzed data from the National Health and Nutrition Examination Survey, a large-scale program that collects health information from participants across the United States. The study focused on data collected between 2011 and 2014. After excluding participants who were under 18 years old, pregnant, or missing key data, the final analysis included 4,871 individuals.
Depression was assessed using the Patient Health Questionnaire-9 (PHQ-9), a widely used tool for measuring depressive symptoms based on the Diagnostic and Statistical Manual of Mental Disorders criteria. Scores on the PHQ-9 range from 0 to 27, with higher scores indicating more severe symptoms. Participants with scores of 10 or higher were classified as having depression.
Muscle mass was measured using dual-energy X-ray absorptiometry, a precise method for determining the lean mass of the arms and legs. Grip strength, a common measure of muscle strength, was assessed with a dynamometer, which measures the maximum force a person can exert with their hands. Each participant performed the grip test three times with each hand, and the researchers used the highest combined score for analysis.
The study revealed a clear negative association between both muscle strength and muscle mass and the likelihood of depression. For every 5-kilogram increase in grip strength, the likelihood of depression decreased by about 5.7%. Participants in the highest quartile of grip strength had a 39.9% lower risk of depression compared to those in the lowest quartile.
Similarly, for every 1-kilogram increase in appendicular lean mass, the likelihood of depression decreased by about 5.5%. Participants in the highest quartile of muscle mass had a 44.1% lower risk of depression compared to those in the lowest quartile.
The researchers also found that these associations were stronger in certain subgroups. For example, the relationship between muscle strength and depression was particularly pronounced in individuals aged 40 to 59, likely due to the natural decline in muscle mass that begins around age 30. Similarly, the link between muscle mass and depression was stronger in men and in individuals with a healthy body mass index.
Interestingly, the study identified potential non-linear trends in the data. For grip strength, there appeared to be a threshold effect: once participants exceeded a certain level of strength, the protective effect against depression plateaued.
The researchers controlled for a range of other factors that could influence the results, including age, gender, race, marital status, education, income, physical activity levels, body mass index, smoking, alcohol consumption, hypertension, and diabetes. But as with all research, there are some caveats to consider. Because the data were collected at a single point in time, the researchers could not determine whether low muscle mass and strength cause depression or whether depression leads to reduced muscle health. Longitudinal studies that track participants over time are needed to clarify this relationship.
Future studies could also explore the mechanisms underlying the relationship between muscle health and depression. For example, physical activity is known to promote the release of brain-derived neurotrophic factor, a protein that supports brain function and mood regulation. Understanding these mechanisms could inform targeted interventions.
“In summary, our study found that lower appendicular lean mass (ALM) and grip strength are associated with an increased likelihood of developing depression,” the researchers concluded. “This finding may inform public health policy makers and clinicians that enhancing muscle mass and strength through exercise could help prevent and mitigate depression. However, further large-scale prospective studies are required to validate our findings.”
The study, “Associations of muscle mass and strength with depression among US adults: A cross-sectional NHANES study,” was conducted by Linjie Qiu, Yan Ren, Jixin Li, Meijie Li, Wenjie Li, Lingli Qin, Chunhui Ning, Jin Zhang, and Feng Gao.
