Study protocol: associations between hormonal profile and physical and cognitive functions in middle-aged men—a one-year cohort follow-up study

Background: Middle age (45–64 years) is a critical yet under-researched phase of aging, during which the first signs of physical, cognitive, and hormonal decline often emerge. In men, testosterone (T) levels begin to decrease starting in the fourth decade of life. However, the relationship between T levels and functional abilities in midlife men remains poorly understood. A better understanding of how physical, cognitive, and hormonal domains interact during this transitional phase is essential for developing targeted interventions to promote healthy aging. Using advanced assessment tools, we propose a study aimed to clarify this association in middle-aged men. Methods: This is a one-year follow-up cohort study. Two hundred healthy middle-aged men will undergo comprehensive assessments, including blood tests, body composition analysis, balance and strength testing, and computerized cognitive evaluation. Half of the sample will perform a subset of the balance and strength tests with a smartphone on their back to obtain accelerometry based measures that have been shown to detect subtle functional changes in midlife. T levels will be measured again after 6 months, and a full assessment will be reperformed after 1 year. Expected results: We anticipate that men with higher T levels will have better physical and cognitive function, with these associations persisting over a one-year period. Conclusion: This study addresses a critical research gap by clarifying the relationships between hormonal, physical, and cognitive function during midlife. If significant associations are identified, T level assessments could be integrated into routine preclinical screenings alongside physical and cognitive evaluations.