http://informahealthcare.com/tam ISSN: 1368-5538 (print), 1473-0790 (electronic) Aging Male, Early Online: 1–6 ! 2015 Informa UK Ltd. DOI: 10.3109/13685538.2015.1046123 ORIGINAL ARTICLE Six weeks of conditioning exercise increases total, but not free testosterone in lifelong sedentary aging men Lawrence D. Hayes 1,2 , Nicholas Sculthorpe 2 , Peter Herbert 3 , Julien S Baker 2 , Roberto Spagna 4 , and Fergal M. Grace 2 1 School of Human Sciences, London Metropolitan University, London, UK, 2 Institute of Clinical Exercise and Health Science, University of the West of Scotland, Hamilton, UK, 3 School of Sport, Health and Outdoor Education, Trinity Saint David, University of Wales, Carmatrthen, UK, and 4 Department of Clinical Biochemistry, Royal Glamorgan Hospital, Pontyclun, Mid Glamorgan, UK Abstract Introduction: Advancing age is associated with a gradual decline in circulating androgens, and the putative role of exercise training on systemic androgens remains to be adequately defined. Methods: The present investigation examined the impact of 6 weeks of supervised exercise training on resting levels of systemic hormones in a cohort of lifelong sedentary men [SED (n ¼ 28), 62.5 ± 5.3 years], compared with a positive control group of age-matched lifelong exercisers [LE (n ¼ 20), 60.4 ± 4.7 years, 4 30 years training history]. Blood hormones were sampled pre- and post-intervention from an antecubital forearm vein and analysed using electrochemiluminescent immunoassay. Cardiorespiratory fitness ( _ VO 2peak ) was determined via indirect calorimetry during an incremental cycle test to volitional exhaustion. Results: Analysis of variance (ANOVA) revealed a lack of significant change in any parameter amongst LE, whilst SED experienced a significant exercise-induced improvement in cardio- respiratory fitness and total testosterone (all p50.05). Concurrent increases in sex hormone- binding globulin (SHBG; p50.05) resulted in a lack of change to either bioavailable or calculated free testosterone (p40.05) amongst SED. Conclusions: Although resting levels of systemic total testosterone increased in response to 6 weeks of exercise training, increases in SHBG negated any potential relationship between calculated-free or bioavailable testosterone. These findings indicate that increases in bioavail- able testosterone fraction are not required for cardiorespiratory fitness improvements in aging men. Keywords Aging, exercise, sex hormone-binding globulin, testosterone History Received 1 March 2015 Revised 26 April 2015 Accepted 26 April 2015 Published online 1 June 2015 Introduction Advancing age is associated with a gradual decline in many physiological functions [1,2] that accompany a concurrent reduction in time spent being physically active [3]. It is well established that both cardiorespiratory fitness (CRF) [1] and peak muscular power output [4] decline with advancing age. These declines are powerful predictors of both independence [2] and risk of morbidity [5]. Indeed, a major obstacle to achieving increased health span, reduced morbidity and optimal longevity in individuals is the decline in physio- logical function that accompanies advancing age [6]. Systemic testosterone (T) concentrations display an analogous pattern of age-associated decline to that of CRF and muscular power [7]. Available longitudinal studies demonstrate this decline in systemic-T to range between 0.4 and 2.6% per year after the age of 40 [8,9], with an accelerated decline during the seventh decade [8]. Conversely, sex hormone-binding globulin (SHBG) is known to increase with age, resulting in a further decline in the biologically active ‘‘free testosterone’’ (free-T) fraction [9]. This decrease in systemic-T is associated with musculoskeletal atrophy and decreased functional cap- acity [10]. Indeed, Folland et al. [11] have observed the age- related decline in knee extensor strength to correlate with free-T, but not total testosterone (TT) in a cohort of aging men. Moreover, Hyde et al. [12] reported free-T, but not total T, was independently associated with frailty in men aged 70–88 years leading to the suggestion that the decline in free- T might be of greater significance to the maintenance of adequate muscle function with advancing age. Acute exercise-induced increases in T concentrations have been widely reported [13–17]. However, despite exercise being a commonly used first-line treatment for mild age- associated T decrements [18,19], it remains unclear whether exercise can potentiate a reversal of the age-associated decline in systemic androgens. Ari and colleagues [20] reported Address for correspondence: L. D. Hayes, School of Human Sciences, London Metropolitan University, Holloway Road, London, N7 8DB, UK. Tel.: +44-020-71334686. E-mail: L.Hayes@Londonmet.ac.uk Aging Male Downloaded from informahealthcare.com by 173.197.223.72 on 06/01/15 For personal use only.