Cardiorespiratory fitness modulates the acute flow-mediated dilation response following high-intensity but not moderate-intensity exercise in elderly men

Bailey, Tom G., Perissiou, Maria, Windsor, Mark, Russell, Fraser, Golledge, Jonathan, Green, Daniel J., and Askew, Christopher D. (2017) Cardiorespiratory fitness modulates the acute flow-mediated dilation response following high-intensity but not moderate-intensity exercise in elderly men. Journal of Applied Physiology, 122 (5). pp. 1238-1248.

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Impaired endothelial function is observed with aging and in those with low cardiorespiratory fitness (VO2peak). Improvements in endothelial function with exercise training are somewhat dependent on the intensity of exercise. While the acute stimulus for this improvement is not completely understood, it may, in part, be due to the flow-mediated dilation (FMD) response to acute exercise. We examined the hypothesis that exercise intensity alters the brachial (systemic) FMD response in elderly men and is modulated by VO2peak. Forty-seven elderly men were stratified into lower (VO2peak = 24.3 +/- 2.9 ml.Kg(-1).min(-1); n = 27) and higher fit groups (VO2peak = 35.4 +/- 5.5 ml.Kg(-1).min(-1); n = 20) after a test of cycling peak power output (PPO). In randomized order, participants undertook moderate-intensity continuous exercise (MICE; 40% PPO) or high-intensity interval cycling exercise (HIIE; 70% PPO) or no-exercise control. Brachial FMD was assessed at rest and 10 and 60 min after exercise. FMD increased after MICE in both groups {increase of 0.86% [95% confidence interval (CI), 0.17-1.56], P = 0.01} and normalized after 60 min. In the lower fit group, FMD was reduced after HIIE [reduction of 0.85% (95% CI, 0.12-1.58), P = 0.02] and remained decreased at 60 min. In the higher fit group, FMD was unchanged immediately after HIIE and increased after 60 min [increase of 1.52% (95% CI, 0.41-2.62), P < 0.01, which was correlated with VO2peak, r = 0.41; P < 0.01]. In the no-exercise control, FMD was reduced in both groups after 60 min (P = 0.05). Exercise intensity alters the acute FMD response in elderly men and VO2peak modulates the FMD response following HIIE but not MICE. The sustained decrease in FMD in the lower fit group following HIIE may represent a signal for vascular adaptation or endothelial fatigue.

NEW & NOTEWORTHY This study is the first to show that moderate-intensity continuous cycling exercise increased flow-mediated dilation (FMD) transiently before normalization of FMD after 1 h, irrespective of cardiorespiratory fitness level in elderly men. Interestingly, we show increased FMD after high-intensity cycling exercise in higher fit men, with a sustained reduction in FMD in lower fit men. The prolonged reduction in FMD after high-intensity cycling exercise may be associated with future vascular adaptation but may also reflect a period of increased cardiovascular risk in lower fit elderly men.

Item ID: 50315
Item Type: Article (Research - C1)
ISSN: 1522-1601
Keywords: exercise, endothelial function, FMD, aging, cardiorespiratory fitness
Funders: National Health and Medical Research Council (NHMRC), Queensland Government
Projects and Grants: NHMRC 1022752, NHMRC 1021416, NHMRC 1020955, NHMRC 1003707, NHMRC 1000967, NHMRC 1019921, NHMRC 1090914
Date Deposited: 20 Sep 2017 07:53
FoR Codes: 32 BIOMEDICAL AND CLINICAL SCIENCES > 3201 Cardiovascular medicine and haematology > 320101 Cardiology (incl. cardiovascular diseases) @ 100%
SEO Codes: 92 HEALTH > 9201 Clinical Health (Organs, Diseases and Abnormal Conditions) > 920103 Cardiovascular System and Diseases @ 100%
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