1. Testosterone In Older Men: Effect Of Exercise
Lawrence D Hayes*1,2, Nicholas Sculthorpe2, Peter Herbert2, Julien S Baker2, Dewi Reed3, Fergal M Grace2
1London Metropolitan University, London, United Kingdom. 2University of the West of Scotland, Hamilton, United Kingdom. 3Royal Glamorgan Hospital, Glamorgan, United Kingdom.
ABSTRACT Advancing age in men is associated with a progressive decline in serum testosterone (T) whilst the tripartite relationship between aging, exercise, and androgens in poorly understood. PURPOSE: The primary aim of this study was to establish the influence of lifelong, and short-term training on serum T, cortisol (C), and sex hormone binding globulin (SHBG) in aging men. METHODS: Serum T, C, and SHBG were compared between two distinct groups consisting lifelong exercising males (LE) and age matched lifelong sedentary individuals (SED) at baseline (week 0) and following six weeks of endurance training for the SED group (week 6). RESULTS: 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 intervention. CONCLUSION: 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, increased SHBG contrived to abrogate increases in free T.
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 declines with advancing age [1]. Systemic testosterone (T) concentrations display an analogous pattern of age-associated decline to that of cardiorespiratory fitness [4]. Available longitudinal studies demonstrate this decline in systemic T to range between 0.4 to 2.6% per year after the age of 40 [5, 6]. However, despite exercise being a commonly used first-line treatment for mild age-associated T decrements [7], it remains unclear whether exercise can potentiate a reversal of the age-associated decline in systemic androgens. With this in mind, the present study examined the impact of six weeks aerobic exercise training programme on systemic sex steroid hormones in a group of otherwise healthy sedentary aging men (SED). These were compared with a positive control group of age-matched lifelong exercisers (LE).
METHODS
Following approval to exercise by their general practitioner, participants provided written informed consent prior to the study which was approved by the University of the West of Scotland Ethics Committee. Twenty eight males (63 ± 5 years, with a stature of 175 ± 6 cm, and body mass of 91 ± 16 kg) participated in the SED group. Twenty males (60 ± 5 years, with a stature of 174 ± 6 cm, and body mass of 79 ± 10 kg) participated in the LE group. Blood samples, body composition, and VO2peak was assessed at two points, separated by six weeks. Serum concentrations of total testosterone (TT), sex hormone binding globulin (SHBG), and cortisol (C) were measured by electrochemiluminescent immunoassay. Free (free-T) and bioavailable T (bio-T) was calculated using the Vermueulen equation [8]. A six week personalised and supervised exercise programme that reflected the ACSM guidelines of 150 mins·wk-1 of moderate and vigorous exercise was prescribed to the SED group. Data were analyzed using a 2 x 2 (Group x Time) mixed design ANOVA. Significance was set a priori at p<0.05 and effect size (ES) are reported for primary outcome measures.
TABLE 1 participant aerobic capacity, cortisol concentration, and body composition for sedentary (sed) and lifelong exercising (le) aging males pre-, and post- six weeks aerobic exercise. v o 2peak = peak aerobic capacity; ffm = fat free mass. data are presented as mean ± sd. *Denotes significant within group differences from week 0 (p<0.05 level). **Denotes significant difference from week 0 (p<0.01). †Denotes significant between group difference (p<0.05).
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POSTER INSTRUCTIONS (continued)
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Week 0 (SED)
Week 6 (SED)
Week 0 (LE)
Week 6 (LE)
Relative VO2peak (ml∙kg∙min-1)
26.9 ± 5.3†
28.6 ± 4.8†*
40.0 ± 5.7
40.5 ± 5.9
Absolute VO2peak (L∙min-1)
2.38 ± 0.46†
2.51 ± 0.43†*
3.05 ± 0.47
3.21 ± 0.52
Cortisol
(nmol∙L-1)
318.2 ± 136.6
307.1 ± 106.4
302.8 ± 134.4
265.5 ± 104.5
Body mass
(kg)
90.44 ± 18.09†
89.28 ± 17.36†**
79.34 ± 13.33
79.78 ± 12.37
FFM
63.8 ± 8.7
64.7 ± 8.0
62.8 ± 5.9
64.1 ± 5.7*
Body fat percentage (%)
28.7 ± 5.0†
26.7 ± 5.2†**
19.7 ± 6.6
18.4 ± 6.5**
RESULTS
No differences between groups were observed for TT, C, SHBG, bio-T, or free-T at week 0 (p>0.05). Significant increases in TT, and SHBG were observed in the SED group after six weeks (p<0.05). TT increased from ± 6.15 to ± 6.89 nmol•L-1 in the SED group (p<0.05, ES=0.716) but not the LE group (14.76 ± 3.17 and ± 4.32 nmol•L-1 at week 0 and 6 respectively [p>0.05]). No effect of training status or intervention was observed for free-T, bio-T (Figure 1), or C (p>0.05). SHBG increased in the SED group from ± to ± nmol•L-1 (p<0.01, ES=0.914) following exercise training, whilst being unaltered amongst LE (48.64 ± and ± nmol•L-1 at week 0 and week 6 respectively [p>0.05]). Body mass and body fat percentage of the SED group were significantly higher than LE at week 0 and week 6 (p<0.05). Percentage body fat decreased in both groups (p<0.001), whilst FFM increased in the LE group (p<0.001) and body mass decreased in the SED group from week 0 to week 6 (p<0.05). Significant increases in VO2peak were observed in the SED group after six weeks (p<0.05, ES=0.627). SED VO2peak was significantly lower than LE (p<0.01) at week 0 and 6 (Table 1). No significant correlations existed between delta changes in hormonal profile (TT, SHBG, bio-T, free-T, and C) and improvements in VO2peak or body composition.
SUMMARY AND CONCLUSION
The main findings of the present study were that six weeks of progressive exercise training increased TT which was mirrored by improvements in VO2peak in otherwise healthy sedentary aging men. However, concomitant increases in SHBG contrived to prevent exercise inducing effect on bio-T or free-T in SED. These findings support the contention that exercise-induced improvements in physiological functioning in sedentary aging men are achieved without concomitant increases in bio-T or free-T fractions.
REFERENCES
1. Edvardsen E, Scient C, Hansen BH, Holme IM, Dyrstad SM, Anderssen SA. Reference values for cardiorespiratory response and fitness on the treadmill in a 20- to 85-year-old population. Chest 2013;144(1): de Oliveira Brito LV, Maranhao Neto GA, Moraes H, Emerick RF, Deslandes AC. Relationship between level of independence in activities of daily living and estimated cardiovascular capacity in elderly women. Arch Gerontol Geriatr 2014;59(2): Talbot LA, Metter EJ, Fleg JL. Leisure-time physical activities and their relationship to cardiorespiratory fitness in healthy men and women years old. Med Sci Sports Exerc 2000;32(2): Araujo AB, Dixon JM, Suarez EA, Murad MH, Guey LT, Wittert GA. Clinical review: Endogenous testosterone and mortality in men: a systematic review and meta-analysis. J Clin Endocrinol Metab 2011;96(10): Harman SM, Metter EJ, Tobin JD, Pearson J, Blackman MR. Longitudinal effects of aging on serum total and free testosterone levels in healthy men. J Clin Endocrinol Metab 2001;86(2): Feldman HA, Longcope C, Derby CA, Johannes CB, Araujo AB, Coviello AD, Bremner WJ, McKinlay JB. Age trends in the level of serum testosterone and other hormones in middle-aged men: Longitudinal results from the Massachusetts Male Aging Study. J Clin Endocrinol Metab 2002;87(2): Swerdloff R, Anawalt BD. Clinical decisions. Testosterone-replacement therapy. N Engl J Med 2014;371(21): Vermeulen A, Verdonck L, Kaufman JM. A critical evaluation of simple methods for the estimation of free testosterone in serum. J Clin Endocrinol Metab 1999;84(10):
 Figure 1 (A); Total Testosterone (Tt) In The Sedentary (Sed) Group And Lifelong Exercising (Le) Group At Week 0 And Week 6 (B); Free Testosterone (Free- t) In The Sed Group And Le Group At Week 0 And Week 6 (C); Bioavailable Testosterone (Bio-t) In The Sed Group And Le Group At Week 0 And Week 6 (D); And Sex Hormone Binding Globulin (Shbg) In The Sed And Le Group At Week 0 And Week 6. Data Are Presented As Mean ± Sd. *Denotes Significant Differences From Week 0 (P<0.05). **Denotes Significant Difference From Week 0 (P<0.01).