Peter Herbert

Does Chronic Exercise Attenuate Age-Related Physiological Decline in Males?

Alteration in body composition, physical function, and substrate metabolism occur with advancing age. These changes can be attenuated by exercise. This study evaluated whether master athletes (MA [n = 20]) would have improved exercise capabilities, anthropometry, and hormone profiles when compared with age-matched sedentary counterparts (S [n = 28]). The MA group was predominantly aerobically trained with some resistance exercise incorporated in their routine. The VO2max, peak power output, and salivary testosterone was significantly higher (p < 0.05) in the MA group, while diastolic blood pressure, systolic blood pressure, and body fat percentage were lower (p < 0.05). Cortisol, fat free mass, (FFM) and total body mass were not significantly different between groups. Salivary testosterone correlated positively with VO2max (r 2 = .320), suggesting that increased aerobic capacity is linked with higher concentrations of testosterone. These results suggest that life-long exercise is associated with favorable body composition and attenuation of the age related decline in testosterone.

The effects of a formal exercise training programme on salivary hormone concentrations and body composition in previously sedentary aging men

Alteration in body composition, physical function, and substrate metabolism occur with advancing age. These changes may be attenuated by exercise. This study examined whether twenty eight, previously sedentary males (62.5 ± 5.3 years of age; body mass of 89.7 ± 16.4 kg) adhering to the ACSM minimum guidelines for aerobic exercise for six weeks would improve exercise capabilities, body composition and salivary hormone profiles. After six weeks of adhering to the guidelines, salivary testosterone and vo2max (absolute and relative) increased (p < 0.05), whilst body fat percentage and body mass decreased (p < 0.05). Peak power output, fat free mass and cortisol values were not significantly different. Interestingly, salivary testosterone correlated inversely with body fat percentage (R2 = .285, p = 0.011). These results suggest that despite previous inactivity, older males can achieve improvements in cardiorespiratory fitness, body composition and anabolism by adhering to simple lifestyle changes.

Validation of a six second cycle test for the determination of peak power output.

The present study examined the agreement between peak power output during a standard Wingate anaerobic test (WAnT) and a six second ‘all-out’ test on a Wattbike Pro. Nine males (40.7 ± 19.4 yrs, 1.76 ± 0.03 cm, 82.11 ± 8.9 kg) underwent three testing protocols on separate days. The protocols consisted 30 second WAnT (WAnT30), a modified WAnT over 6 seconds (WAnT6) and a 6 second peak power test (PPT6). PPT6 was correlated with WAnT30 (r = 0.9; p < 0.001) with a mean bias of 105 W. PPT6 correlated with WAnT6 (r = 0.95; p < 0.001) with a mean bias of 74 W. WAnT6 correlated with WAnT30 (r = 0.99; p < 0.001) with a mean bias of 31 W. There was no difference in time to peak power between any trial. PPT6 resulted in significantly greater power outputs than in WAnT30 and WAnT6 (p < 0.001). We conclude that PPT6 and WAnT6 are valid measures of peak power output compared with WAnT30. This identifies that PPT6 and WAnT6 as short duration ‘all-out’ tests that have practical applications for researchers and coaches who wish to assess peak power output without the fatiguing effects associated with a standard WAnT.

Age related vascular endothelial function following lifelong sedentariness: positive impact of cardiovascular conditioning without further improvement following low frequency high intensity interval training

Aging is associated with diffuse impairments in vascular endothelial function and traditional aerobic exercise is known to ameliorate these changes. High intensity interval training (HIIT) is effective at improving vascular function in aging men with existing disease, but its effectiveness remains to be demonstrated in otherwise healthy sedentary aging. However, the frequency of commonly used HIIT protocols may be poorly tolerated in older cohorts. Therefore, the present study investigated the effectiveness of lower frequency HIIT (LfHIIT) on vascular function in a cohort of lifelong sedentary (SED; n = 22, age 62.7 ± 5.2 years) men compared with a positive control group of lifelong exercisers (LEX; n = 17, age 61.1 ± 5.4 years). The study consisted of three assessment phases; enrolment to the study (Phase A), following 6 weeks of conditioning exercise in SED (Phase B) and following 6 weeks of low frequency HIIT in both SED and LEX (LfHIIT; Phase C). Conditioning exercise improved FMD in SED (3.4 ± 1.5% to 4.9 ± 1.1%; P < 0.01) such that the difference between groups on enrolment (3.4 ± 1.5% vs. 5.3 ± 1.4%; P < 0.01) was abrogated. This was maintained but not further improved following LfHIIT in SED whilst FMD remained unaffected by LfHIIT in LEX. In conclusion, LfHIIT is effective at maintaining improvements in vascular function achieved during conditioning exercise in SED. LfHIIT is a well‐tolerated and effective exercise mode for reducing cardiovascular risk and maintaining but does not improve vascular function beyond that achieved by conditioning exercise in aging men, irrespective of fitness level.

Six weeks of conditioning exercise increases total, but not free testosterone in lifelong sedentary aging men

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 = 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 () 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.

Resting steroid hormone concentrations in lifetime exercisers and lifetime sedentary males

Abstract Introduction: Advancing age in men is associated with a progressive decline in serum testosterone (T) and interactions between exercise, aging and androgen status are poorly understood. 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. A secondary aim was to determine the agreement between serum and salivary measurement of steroid hormones in ageing men. Methods: Serum and salivary steroid hormones (serum C, T and SHBG, and salivary measures of C and T) were determined and compared between two distinct groups; lifelong exercising males (LE [n = 20], 60.4 ± 4.7 year) 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, while Mann-Whitney U revealed a lack of differences in total T (TT), bioavailable T (bio-T) or free testosterone (free-T). Further, salivary T (sal-T) did not correlate with serum markers of T in LE, SED, or when pooled (r = 0.040; p > 0.05). Conclusions: Findings from this investigation suggested that resting levels of serum T and calculated free-T was unable to distinguish between diverse lifelong training histories in aging men. Further, sal-T was not an appropriate indicator of serum T and calculated free-T values in older males and considerable caution should be exercised when interpreting sal-T measurements in aging males.

Poor levels of agreement between serum and saliva testosterone measurement following exercise training in aging men

Abstract Testosterone (T) is a biologically important androgen that demonstrates a widely-known natural decline with advancing age. The use of salivary T (sal-T), as a determinant of systemic T, has shown promising results in recent years. However, the strength of the salivary-serum T relationship may be affected by measurement method and binding capacity with salivary proteins. The potential influence exercise may impact on this relationship is unstudied in aging men. Therefore, the aim of the present investigation was to examine the relationship of the delta change (Δ) in sal-T with Δserum T following six weeks exercise training. Fifteen sedentary (SED) males (aged 60.4 ± 5.0 years of age) and 20 lifelong exercising (LE) males (60.4 ± 4.7 years of age) were participated. Pearson’s correlation coefficient revealed sal-T did not correlate with total testosterone (TT), sex hormone binding globulin (SHBG), bioactive T (bio-T), or free T (free-T) at week 0 or week 6. Δsal-T did not correlate with ΔTT, ΔSHBG, Δbio-T or Δfree-T (r = 0.271, p = 0.180; r = 0.197, p = 0.335; r = 0.258, p = 0.205; and r = 0.257, p = 0.205, respectively). In conclusion, poor levels of agreement existed between saliva and serum measurements of T in response to exercise amongst aging men.

One session of high-intensity interval training (HIIT) every 5 days, improves muscle power but not static balance in lifelong sedentary ageing men: A randomized controlled trial.

Background: Declining muscle power during advancing age predicts falls and loss of independence. High-intensity interval training (HIIT) may improve muscle power, but remains largely unstudied in ageing participants. Methods: This randomized controlled trial (RCT) investigated the efficacy of a low-frequency HIIT (LfHIIT) intervention on peak muscle power (peak power output [PPO]), body composition, and balance in lifelong sedentary but otherwise healthy males. Methods: Thirty-three lifelong sedentary ageing men were randomly assigned to either intervention (INT; n = 22, age 62.3 ± 4.1 years) or control (n = 11, age 61.6 ± 5.0 years) who were both assessed at 3 distinct measurement points (phase A), after 6 weeks of conditioning exercise (phase B), and after 6 weeks of HIIT once every 5 days in INT (phase C), where control remained inactive throughout the study. Results: Static balance remained unaffected, and both absolute and relative PPO were not different between groups at phases A or B, but increased significantly in INT after LfHIIT (P < 0.01). Lean body mass displayed a significant interaction (P < 0.01) due to an increase in INT between phases B and C (P < 0.05). Conclusions: 6 weeks of LfHIIT exercise feasible and effective method to induce clinically relevant improvements in absolute and relative PPO, but does not improve static balance in sedentary ageing men.

Exercise training improves free testosterone in lifelong sedentary aging men

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-week 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.

Low-Frequency High-Intensity Interval Training is an Effective Method to Improve Muscle Power in Lifelong Sedentary Aging Men: A Randomized Controlled Trial

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