Testosterone in older men: effect of exercise

Advancing age in men is associated with a progressive decline in serum testosterone (T) and interactions between exercise, aging, and androgen status are only partially understood.PURPOSE: The primary aim of this study was to establish the influence of lifelong training history on serum T, cortisol (C), and sex hormone binding globulin (SHBG) in aging men.METHODS: Serum T, C, and SHBG were determined by radioimmunoassay (RIA) and compared between two distinct groups consisting lifelong exercising males (LE [n=20], 60.4 ± 4.7 yr) and age matched lifelong sedentary individuals (SED [n=28], 62.5 ± 5.3 years).RESULTS: T-test revealed a lack of significant differences for serum C or SHBG between LE and SED, whilst Mann-Whitney U revealed no difference in total T, bioavailable T, or free T. ANOVA revealed significant exercise induced increases in aerobic capacity, serum T and serum SHBG (each p<0.05) but not free T or bioavailable T in the SED group following the intervention.CONCLUSION: Findings from this investigation indicate that resting levels of serum T, and calculated free and bioavailable T do not differ in aging men, irrespective of lifelong exercise history. The present study found small but significant increases in resting levels of systemic T following exercise training in SED. However this may not be available to any exert biological effect as a result of the corresponding increase in the (SHBG) protein fraction, and further supported by the lack of any impact on free T