Aortic augmentation index in endurance athletes : A role for cardiorespiratory fitness
- Denham, Joshua, Brown, Nicholas, Tomaszewski, Maciej, Williams, Bryan, O’Brien, Brendan, Charchar, Fadi
- Authors: Denham, Joshua , Brown, Nicholas , Tomaszewski, Maciej , Williams, Bryan , O’Brien, Brendan , Charchar, Fadi
- Date: 2016
- Type: Text , Journal article
- Relation: European Journal of Applied Physiology Vol. 116, no. 8 (2016), p. 1537-1544
- Relation: http://purl.org/au-research/grants/nhmrc/1009490
- Full Text: false
- Reviewed:
- Description: Purpose: Endurance exercise improves cardiovascular health and reduces mortality risk. Augmentation index (AIx) reflects adverse loading exerted on the heart and large arteries and predicts future cardiovascular disease. The purpose of this study was to establish whether endurance athletes possess lower AIx and aortic blood pressure compared to healthy controls, and to determine the association between AIx and cardiorespiratory fitness. Methods: Forty-six endurance athletes and 43 healthy controls underwent central BP and AIx measurements by non-invasive applanation tonometry before a maximal exercise test. Peak oxygen uptake (V˙ O 2 peak) was assessed by pulmonary analysis. Results: Relative to controls, athletes had significantly lower brachial diastolic blood pressure (BP, −4.8 mmHg, p < 0.01), central systolic BP (−3.5 mmHg, p = 0.07), and AIx at a heart rate of 75 beats min−1 (AIx@75, −11.9 %, p < 0.001). No AIx@75 differences were observed between athletes and controls when adjusted for age and V˙ O 2 peak [athletes vs controls mean (%) ± SE: −6.9 ± 2.2 vs −5.7 ± 2.3, p = 0.76]. Relative to men with low V˙ O 2 peak, those with moderate and high V˙ O 2 peak had lower age-adjusted AIx@75 (p < 0.001). In women, those with high V˙ O 2 peak had lower AIx@75 than those with low and moderate V˙ O 2 peak (p < 0.01). Conclusions: The lower AIx@75 in endurance athletes is partly mediated by V˙ O 2 peak. While an inverse relationship between AIx@75 and V˙ O 2 peak was found in men, women with the highest V˙ O 2 peak possessed lowest AIx@75 compared to females with moderate or poor cardiorespiratory fitness. We recommend aerobic training aimed at achieving a minimum V˙ O 2 peak of 45 ml kg−1 min−1 to decrease the risk of future cardiovascular events and all-cause mortality.
- Description: Purpose: Endurance exercise improves cardiovascular health and reduces mortality risk. Augmentation index (AIx) reflects adverse loading exerted on the heart and large arteries and predicts future cardiovascular disease. The purpose of this study was to establish whether endurance athletes possess lower AIx and aortic blood pressure compared to healthy controls, and to determine the association between AIx and cardiorespiratory fitness. Methods: Forty-six endurance athletes and 43 healthy controls underwent central BP and AIx measurements by non-invasive applanation tonometry before a maximal exercise test. Peak oxygen uptake (V˙ O 2 peak) was assessed by pulmonary analysis. Results: Relative to controls, athletes had significantly lower brachial diastolic blood pressure (BP, −4.8 mmHg, p < 0.01), central systolic BP (−3.5 mmHg, p = 0.07), and AIx at a heart rate of 75 beats min−1 (AIx@75, −11.9 %, p < 0.001). No AIx@75 differences were observed between athletes and controls when adjusted for age and V˙ O 2 peak [athletes vs controls mean (%) ± SE: −6.9 ± 2.2 vs −5.7 ± 2.3, p = 0.76]. Relative to men with low V˙ O 2 peak, those with moderate and high V˙ O 2 peak had lower age-adjusted AIx@75 (p < 0.001). In women, those with high V˙ O 2 peak had lower AIx@75 than those with low and moderate V˙ O 2 peak (p < 0.01). Conclusions: The lower AIx@75 in endurance athletes is partly mediated by V˙ O 2 peak. While an inverse relationship between AIx@75 and V˙ O 2 peak was found in men, women with the highest V˙ O 2 peak possessed lowest AIx@75 compared to females with moderate or poor cardiorespiratory fitness. We recommend aerobic training aimed at achieving a minimum V˙ O 2 peak of 45 ml kg−1 min−1 to decrease the risk of future cardiovascular events and all-cause mortality. © 2016, Springer-Verlag Berlin Heidelberg.
Increased expression of telomere-regulating genes in endurance athletes with long leukocyte telomeres
- Denham, Joshua, O'Brien, Brendan, Prestes, Priscilla, Brown, Nicholas, Charchar, Fadi
- Authors: Denham, Joshua , O'Brien, Brendan , Prestes, Priscilla , Brown, Nicholas , Charchar, Fadi
- Date: 2015
- Type: Text , Journal article
- Relation: Journal of Applied Physiology Vol. 120, no. 2 (2015), p. 148-158
- Relation: http://purl.org/au-research/grants/nhmrc/1009490
- Full Text:
- Reviewed:
- Description: Leukocyte telomeres shorten with age, and excessive shortening is associated with age-related cardiometabolic diseases. Exercise training may prevent disease through telomere length maintenance although the optimal amount of exercise that attenuates telomere attrition is unknown. Furthermore, the underlying molecular mechanisms responsible for the enhanced telomere maintenance observed in endurance athletes is poorly understood. We quantified the leukocyte telomere length and analyzed the expression of telomere-regulating genes in endurance athletes and healthy controls (both n = 61), using quantitative PCR. We found endurance athletes have significantly longer (7.1%, 208-416 nt) leukocyte telomeres and upregulated TERT (2.0-fold) and TPP1 (1.3-fold) mRNA expression compared with controls in age-adjusted analysis. The telomere length and telomere-regulating gene expression differences were no longer statistically significant after adjustment for resting heart rate and relative (V) over dotO(2 max) (all P > 0.05). Resting heart rate emerged as an independent predictor of leukocyte telomere length and TERT and TPP1 mRNA expression in stepwise regression models. To gauge whether volume of exercise was associated with leukocyte telomere length, we divided subjects into running and cycling tertiles (distance covered per week) and found individuals in the middle and highest tertiles had longer telomeres than individuals in the lowest tertile. These data emphasize the importance of cardiorespiratory fitness and exercise training in the prevention of biological aging. They also support the concept that moderate amounts of exercise training protects against biological aging, while higher amounts may not elicit additional benefits.
- Authors: Denham, Joshua , O'Brien, Brendan , Prestes, Priscilla , Brown, Nicholas , Charchar, Fadi
- Date: 2015
- Type: Text , Journal article
- Relation: Journal of Applied Physiology Vol. 120, no. 2 (2015), p. 148-158
- Relation: http://purl.org/au-research/grants/nhmrc/1009490
- Full Text:
- Reviewed:
- Description: Leukocyte telomeres shorten with age, and excessive shortening is associated with age-related cardiometabolic diseases. Exercise training may prevent disease through telomere length maintenance although the optimal amount of exercise that attenuates telomere attrition is unknown. Furthermore, the underlying molecular mechanisms responsible for the enhanced telomere maintenance observed in endurance athletes is poorly understood. We quantified the leukocyte telomere length and analyzed the expression of telomere-regulating genes in endurance athletes and healthy controls (both n = 61), using quantitative PCR. We found endurance athletes have significantly longer (7.1%, 208-416 nt) leukocyte telomeres and upregulated TERT (2.0-fold) and TPP1 (1.3-fold) mRNA expression compared with controls in age-adjusted analysis. The telomere length and telomere-regulating gene expression differences were no longer statistically significant after adjustment for resting heart rate and relative (V) over dotO(2 max) (all P > 0.05). Resting heart rate emerged as an independent predictor of leukocyte telomere length and TERT and TPP1 mRNA expression in stepwise regression models. To gauge whether volume of exercise was associated with leukocyte telomere length, we divided subjects into running and cycling tertiles (distance covered per week) and found individuals in the middle and highest tertiles had longer telomeres than individuals in the lowest tertile. These data emphasize the importance of cardiorespiratory fitness and exercise training in the prevention of biological aging. They also support the concept that moderate amounts of exercise training protects against biological aging, while higher amounts may not elicit additional benefits.
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