Exercise training improves free testosterone in lifelong sedentary aging men
- Hayes, Lawrence, Herbert, Peter, Sculthorpe, Nicholas, Grace, Fergal
- Authors: Hayes, Lawrence , Herbert, Peter , Sculthorpe, Nicholas , Grace, Fergal
- Date: 2017
- Type: Text , Journal article
- Relation: Endocrine Connections Vol.6 , no.5 (2017), p.306-310
- Full Text:
- Reviewed:
- Description: As the impact of high intensity interval training (HIIT) on systemic hormones in aging men is unstudied to date, we investigated whether total testosterone (TT), sex hormone binding globulin (SHBG), free testosterone (free-T), and cortisol (all in serum) were altered following HIIT in a cohort of 22 lifelong sedentary (62 +/- 2 years) older men. As HIIT requires preconditioning exercise in sedentary cohorts, participants were tested at three phases, each separated by six weeks' training; baseline (phase A), following conditioning exercise (phase B), and post-HIIT (phase C). Each measurement phase used identical methods. TT was significantly increased following HIIT (~17%; P<0.001) with most increase occurring during preconditioning (~10%; P=0.007). Free-T was unaffected by conditioning exercise (P=0.102) but was significantly higher following HIIT compared to baseline (~4.5%; P=0.023). Cortisol remained unchanged from A to C (P=0.138). The present data indicate a combination of preconditioning and HIIT increases TT and SHBG in sedentary older males, with the HIIT stimulus accounting for a small but statistically significant increase in free-T. Further study is required to determine the biological importance of small improvements in free-T in aging men.
- Authors: Hayes, Lawrence , Herbert, Peter , Sculthorpe, Nicholas , Grace, Fergal
- Date: 2017
- Type: Text , Journal article
- Relation: Endocrine Connections Vol.6 , no.5 (2017), p.306-310
- Full Text:
- Reviewed:
- Description: As the impact of high intensity interval training (HIIT) on systemic hormones in aging men is unstudied to date, we investigated whether total testosterone (TT), sex hormone binding globulin (SHBG), free testosterone (free-T), and cortisol (all in serum) were altered following HIIT in a cohort of 22 lifelong sedentary (62 +/- 2 years) older men. As HIIT requires preconditioning exercise in sedentary cohorts, participants were tested at three phases, each separated by six weeks' training; baseline (phase A), following conditioning exercise (phase B), and post-HIIT (phase C). Each measurement phase used identical methods. TT was significantly increased following HIIT (~17%; P<0.001) with most increase occurring during preconditioning (~10%; P=0.007). Free-T was unaffected by conditioning exercise (P=0.102) but was significantly higher following HIIT compared to baseline (~4.5%; P=0.023). Cortisol remained unchanged from A to C (P=0.138). The present data indicate a combination of preconditioning and HIIT increases TT and SHBG in sedentary older males, with the HIIT stimulus accounting for a small but statistically significant increase in free-T. Further study is required to determine the biological importance of small improvements in free-T in aging men.
Six weeks of conditioning exercise increases total, but not free testosterone in lifelong sedentary aging men
- Hayes, Lawrence, Sculthorpe, Nicholas, Herbert, Peter, Baker, Julien, Spagna, Roberto, Grace, Fergal
- Authors: Hayes, Lawrence , Sculthorpe, Nicholas , Herbert, Peter , Baker, Julien , Spagna, Roberto , Grace, Fergal
- Date: 2015
- Type: Text , Journal article
- Relation: Aging Male Vol. 18, no. 3 (2015), p. 195-200
- Full Text:
- Reviewed:
- Description: 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 = 28), 62.5 +/- 5.3 years], compared with a positive control group of age-matched lifelong exercisers [LE (n = 20), 60.4 +/- 4.7 years, >30 years training history]. Blood hormones were sampled pre- and post-intervention from an antecubital forearm vein and analysed using electrochemiluminescent immunoassay. Cardiorespiratory fitness ([Formula: see text]) 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 cardiorespiratory fitness and total testosterone (all p < 0.05). Concurrent increases in sex hormone-binding globulin (SHBG; p < 0.05) resulted in a lack of change to either bioavailable or calculated free testosterone (p > 0.05) 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 bioavailable testosterone fraction are not required for cardiorespiratory fitness improvements in aging men.
- Authors: Hayes, Lawrence , Sculthorpe, Nicholas , Herbert, Peter , Baker, Julien , Spagna, Roberto , Grace, Fergal
- Date: 2015
- Type: Text , Journal article
- Relation: Aging Male Vol. 18, no. 3 (2015), p. 195-200
- Full Text:
- Reviewed:
- Description: 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 = 28), 62.5 +/- 5.3 years], compared with a positive control group of age-matched lifelong exercisers [LE (n = 20), 60.4 +/- 4.7 years, >30 years training history]. Blood hormones were sampled pre- and post-intervention from an antecubital forearm vein and analysed using electrochemiluminescent immunoassay. Cardiorespiratory fitness ([Formula: see text]) 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 cardiorespiratory fitness and total testosterone (all p < 0.05). Concurrent increases in sex hormone-binding globulin (SHBG; p < 0.05) resulted in a lack of change to either bioavailable or calculated free testosterone (p > 0.05) 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 bioavailable testosterone fraction are not required for cardiorespiratory fitness improvements in aging men.
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