Effects of Age and Long-Term Endurance Training on V·O2 Kinetics

Grey, Tyler M.; Spencer, Matthew D.; Belfry, Glen R.; Kowalchuk, John M.; Paterson, Donald H.; Murias, Juan M.

doi:10.1249/mss.0000000000000398

Cited by 38 publications

(41 citation statements)

References 82 publications

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“…Additionally, sex hormone-binding globulin (SHBG) is positively correlated with age, thereby attenuating the unbound fraction of testosterone, which is available for androgen receptor interactions (4, 5). With the age-associated reduction in anabolic hormone production, reductions in cardiorespiratory fitness (6), muscle strength (7) and muscle power (8) are also observed. Furthermore, significant correlations between testosterone and measures of physical performance in older adults have been observed (9).…”

Section: Introductionmentioning

confidence: 99%

Exercise training improves free testosterone in lifelong sedentary aging men

Hayes

Herbert

Sculthorpe

et al. 2017

Endocrine Connections

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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.

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Section: Introductionmentioning

confidence: 99%

Exercise training improves free testosterone in lifelong sedentary aging men

Hayes

Herbert

Sculthorpe

et al. 2017

Endocrine Connections

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“…Recently, our laboratory has proposed that improvements in O 2 delivery and/or distribution to the active tissues play a critical role in the speeding of

{\dot{normalV} O}_{2}

kinetics observed after an exercise training intervention (Murias et al., 2010b,c) or in chronically trained individuals (Grey et al., ). Others, however, have proposed that in young healthy individuals, improvements in O 2 extraction (Bailey et al., ) and/or enhanced intracellular metabolic control (i.e., faster activation of pyruvate dehydrogenase and other oxidative enzymes; McKay et al., ) are mainly responsible for the faster

{\dot{normalV} O}_{2}

kinetics observed shortly after the commencement of an exercise training program.…”

mentioning

confidence: 99%

Effects of short‐term training and detraining on VO₂ kinetics: Faster VO₂ kinetics response after one training session

Murias

Edwards

Paterson

2015

Scandinavian Med Sci Sports

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This study examined the time course of short-term training and detraining-induced changes in oxygen uptake ( V ˙ O 2 ) kinetics. Twelve men (24 ± 3 years) were assigned to either a 50% or a 70% of V ˙ O 2 m a x training intensity (n = 6 per group). V ˙ O 2 was measured breath-by-breath. Changes in deoxygenated-hemoglobin concentration (Δ[HHb]) were measured by near-infrared spectroscopy. Moderate-intensity exercise on-transient V ˙ O 2 and Δ[HHb] were modeled with a mono-exponential and normalized (0-100% of response) and the [ H H b ] / V ˙ O 2 ratio was calculated. Similar changes in time constant of V ˙ O 2 ( t V ˙ O 2 ) were observed in both groups. The combined group mean for t V ˙ O 2 decreased ∼14% (32.3 to 27.9 s, P < 0.05) after one training session with a further ∼11% decrease (27.9 to 24.8 s, P < 0.05) following two training sessions. The t V ˙ O 2 p remained unchanged throughout the remaining of training and detraining. A significant "overshoot" in the [ H H b ] / V ˙ O 2 ratio was decreased (albeit not significant) after one training session, and abolished (P < 0.05) after the second one, with no overshoot observed thereafter. Speeding of V ˙ O 2 kinetics was remarkably quick with no further changes being observed with continuous training or during detraining. Improve matching of local O2 delivery to O2 utilization is a mechanism proposed to influence this response.

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“…Importantly, recent studies have shown that different interventions can decrease TV O 2 in older individuals to values similar to those observed in their young counterparts (23,39,57,58), opening the debate as to whether aging per se, or other factors that normally accompany, but are not requisite with, aging (such as poorer cardiovascular function and decreased mitochondrial enzymes activity likely related to reduced fitness levels), is responsible for the slower rate of adjustment in the V O 2 response in the elderly.…”

mentioning

confidence: 73%

“…Indeed, in three other studies in which V O 2 kinetics responses were compared in older and young individuals, the rate of adjustment of oxidative phosphorylation was similar between groups (12,13,38). In addition, a recent paper has demonstrated that older, chronically trained men have V O 2 kinetics that is similar to those of young individuals (39). This is an important characteristic of this response, as it shows not only that some older participants might display a ''fast'' V O 2 kinetics but also that young, healthy individuals might exhibit a ''slow'' response as previously demonstrated (62,63).…”

Section: O 2 Kinetics In Older Adultsmentioning

confidence: 90%