An analysis of UK Biobank data indicates that individuals with greater handgrip strength tend to have lower volumes of white matter hyperintensities (WMHs) in their brains. Their white matter also appears to have a more intact microstructure—that is, it shows fewer signs of microstructural injury. The study was published in the Journal of Cachexia, Sarcopenia and Muscle.
Cerebral WMHs are bright areas that appear on certain types of magnetic resonance imaging (MRI) brain scans. They are commonly found in older adults and are often considered a feature of aging, but they can also occur in younger individuals with specific health conditions. WMHs are believed to reflect small vessel disease, involving chronic reductions in blood flow or damage to the small arteries within the brain.
These lesions are most frequently located in the periventricular and deep white matter regions—areas composed primarily of myelinated nerve fibers that connect different parts of the brain. Although often not accompanied by overt psychological symptoms, larger WMH volumes have been linked to cognitive decline, slower processing speed, and an increased risk of dementia.
WMHs are also associated with stroke, depression, and gait disturbances. Risk factors include hypertension, diabetes, smoking, and other cardiovascular conditions. As such, WMHs are an important biomarker in neurological research and clinical assessments of brain health. Higher WMH volume suggests that the white matter structure is more disrupted and that more injuries are present.
Study author Yuna Li and her colleagues sought to explore the links between handgrip strength and blood testosterone concentrations with WMH volume and microstructural injury in brain white matter. They noted that skeletal muscles make up approximately 40% of body weight and play a critical role in promoting blood circulation. Lower muscle strength has been linked to poorer health outcomes.
Previous studies have indicated that handgrip strength may be associated with WMH volume, particularly in men. Handgrip strength measures the force exerted when squeezing an object with the hand and is commonly used as an indicator of overall muscle strength and functional health.
The researchers analyzed data from the UK Biobank, a large-scale research initiative that includes data on over 500,000 individuals from the United Kingdom. The Biobank contains a wide range of information, including demographic characteristics, lifestyle factors, medication and surgery history, biological samples, and neuroimaging. For this study, the authors focused on participants for whom both brain MRI scans and serum total testosterone measurements were available.
The final sample included 34,832 participants, of whom approximately 51% were male. On average, the men in the study were older, more likely to be smokers and alcohol consumers, and had higher handgrip strength, testosterone levels, body mass index (BMI), and a higher prevalence of conditions such as diabetes compared to women.
The results showed that individuals with greater handgrip strength tended to have lower WMH volume. Their brain white matter also exhibited healthier microstructure, with fewer signs of damage. Higher testosterone levels were also associated with lower WMH volume in both men and women. Additional statistical analyses suggested that about 1–2% of the relationship between handgrip strength and WMH volume could be explained by testosterone levels.
“Our study revealed that greater HGS [hand grip strength] was linearly associated with reduced WMH volume and less white matter microstructural injury, mediated by STT [serum total testosterone, the amount of testosterone circulating in the bloodstream]. Improving muscle function may contribute to deferring white matter damage and preventing stroke and dementia, offering a feasible secondary prevention measure for CSVD [cerebral small vessel disease],” the study authors concluded.
The study sheds light on the links between hand grip strength and white matter microstructural integrity in the brain. However, it should be noted that study authors assessed WMH volume across the entire brain and not in specific areas. These associations might differ between different areas of the brain.
The paper, “Associations of Handgrip Strength and Testosterone With Cerebral White Matter Hyperintensity and Microstructural Injury,” was authored by Yuna Li, Shan Tian, Yuan Qiao, Chaohua Cong, Junting Yang, Shanshan Cao, Xirui Zhu, Lei Zhao, Panlong Li, and Jingjing Su.