Peak oxygen uptake, ventilatory threshold, and arterial stiffness in adolescents

Cardiorespiratory Fitness Is an Indicator of Arterial Stiffness and Aortic Blood Pressure in Healthy Adolescents

Background/Objectives: We aimed to investigate the influence of cardiorespiratory fitness (CRF) and body composition on arterial stiffness. Methods: Carotid-to-femoral pulse wave velocity (cfPWV) and aortic systolic (ASBP) and diastolic (ADBP) blood pressure were compared between upper and lower tertiles of oxygen consumption at the aerobic threshold (VO2AerT), peak oxygen consumption (VO2peak), percentage of fat mass (FM%), and body mass index (BMI) in sixty adolescents (30 males and 30 females, 14.9 ± 2.1 years old). A stepwise multivariable linear regression analysis was performed to investigate the independent associations between VO2AerT and VO2peak and cfPWV, and between BMI and FM% and cfPWV with adjustments for age, sex, ASBP, and ADBP. Results: cfPWV and ADBP were lower in the second and third VO2AerT tertiles compared to the first tertile (cfPWV, 4.7 ± 0.5 and 4.7 ± 0.5 vs. 5.3 ± 0.8 m/s, p < 0.01; ADBP, 62 ± 7 and 62 ± 7 vs. 70 ± 8 mmHg, p < 0.01). ASBP was lower in the third VO2AerT tertile compared to the first tertile (94 ± 7 vs. 101 ± 12 mmHg, p = 0.05). ADBP was lower in the second VO2peak tertile compared to the first tertile (62 ± 7 vs. 68 ± 9 mmHg, p = 0.03). ASBP was lower in the first and second BMI tertiles compared to the third tertile (95 ± 8 and 95 ± 7 vs. 102 ± 11 mmHg, p = 0.02). The eight-variable model significantly contributed to the variance of cfPWV (F(8, 51) = 7.450, p < 0.01), accounting for 47% of the variance. Individually, age (p < 0.05) and ADBP (p < 0.01) significantly predicted cfPWV. Conclusions: Submaximal indicators of CRF such as VO2AerT should be considered as a part of the risk stratification of cardiovascular disease in healthy adolescents.

Evaluation of salivary α-amylase and immunoglobulin A responses after endurance exercise in adolescent males and females with similar aerobic fitness

The objective of this study was to clarify whether there are sex-specific differences in salivary α-amylase and immunoglobulin A responses following acute endurance exercise in adolescent males and females with equivalent cardiorespiratory fitness levels. Twenty-six aerobically trained adolescent males and females with similar training status were enrolled in this study. Each individual executed a 1-h prolonged cycling exercise corresponding to a constant power output at 65% of peak oxygen uptake. Unstimulated whole salivary samples were taken with the passive drooling method at the 10-min period before and after exercise for the determination of salivary responses [α-amylase, immunoglobulin A, total protein and flow rate]. Salivary α-amylase activity, immunoglobulin A concentration and total protein concentration were significantly augmented immediately after acute endurance exercise. Regarding sex differences, only the salivary flow rate was significantly lower in females than in males. The findings of the present study imply that adolescent males and females appear to have similar salivary responses after acute endurance exercise, as represented by salivary α-amylase activity and immunoglobulin A concentration in connection with total protein concentration and salivary flow rate, when they are matched for peak oxygen uptake relative to fat-free body mass.

Associations of cardiorespiratory fitness, body composition, and blood pressure with arterial stiffness in adolescent, young adult, and middle-aged women

Few studies have investigated whether higher cardiorespiratory fitness (CRF) or favourable body composition are related to lower arterial stiffness in women. We therefore investigated the associations of CRF, body fat percentage (BF%), fat free mass index (FFMI), and mean arterial pressure (MAP) with arterial stiffness in 146 women aged 16-58 years. CRF was assessed by a maximal exercise test with respiratory gas analysis either on a cycle ergometer or a treadmill. Aortic pulse wave velocity (PWVao), augmentation index (AIx%), and MAP were assessed by a non-invasive oscillometric device and BF% and FFMI by a bioelectrical impedance or DXA device. CRF was inversely associated with PWVao (β =  - 0.004, 95% CI - 0.005 to - 0.002) and AIx% (β =  - 0.075, 95% CI - 0.102 to - 0.048) and these associations remained similar after adjustment for BF% or MAP, but not after the adjustment for age. FFMI was inversely associated with PWVao (β =  - 0.010, 95% CI - 0.019 to - 0.002) and MAP directly associated with PWVao (β = 0.005, 95% CI 0.003 to 0.006) and AIx% (β = 0.092, 95% CI 0.069 to 0.116) and the associations with PWVao also remained after further adjustments for BF% and age. In conclusion, a higher FFMI and a lower MAP were independently associated with lower arterial stiffness.

The mediating role of adiposity in the longitudinal association between cardiorespiratory fitness and blood pressure in adolescents: LabMed cohort study

BACKGROUND

The aim of this prospective cohort study was to examine whether the association between the cardiorespiratory fitness (CRF) at baseline and blood pressure (BP) at follow-up is mediated by adiposity in adolescents.

MATERIALS AND METHODS

The sample comprised 734 adolescents (349 girls) aged 12-18 years from the LabMed Physical Activity Cohort Study. The variables of interest were measured in 2011 (baseline) and in 2013 (2-year follow-up). CRF was assessed by the 20-m shuttle run test. Body mass index, waist circumference, body fat percentage, pubertal status and resting BP were assessed according to standard procedures. Boot-strapped mediation procedures were performed, and indirect effects (IE) with confidence intervals (CI) not including zero were considered statistically significant.

RESULTS

After adjusting for potential confounders, body mass index acted as a mediator of the relationship between CRF and systolic BP (IE = -0. 023; CI = -0.039; -0.009), pulse pressure (IE = -0.023; CI = -0.034; -0.012) and rate product pressure (IE = -2.839; CI = -5.329; -0.340). Similar results were obtained for waist circumference as mediator for systolic BP (IE = -0.019; CI = -0.033; -0.005), pulse pressure (IE = -0.017; CI = -0.028; -0.007) and rate product pressure (IE = -3.793; CI = -6.097; -1.689). Likewise, body fat percentage mediated the association for: systolic BP (IE = -0.029; CI = -0.048; -0.010), pulse pressure (IE = -0.027; CI = -0.041; -0.013) and rate product pressure (IE = -4.280; CI = -7.488; -1.264).

CONCLUSIONS

Adiposity mediated the association between CRF and BP in adolescents. Therefore, both optimal CRF and adiposity levels are important to maintain normal BP ranges throughout adolescence.

Aerobic capacity and respiratory patterns are better in recreational basketball-engaged university students than age-matched untrained males

Study aim: To asses and compare the aerobic capacity and respiratory parameters in recreational basketball-engaged university students with age-matched untrained young adults.

Material and methods: A total of 30 subjects were selected to took part in the study based on recreational-basketball activity level and were assigned to a basketball (BG: n = 15, age 22.86 ± 1.35 yrs., body height 185.07 ± 5.95 cm, body weight 81.21 ± 6.15 kg) and untrained group (UG: n = 15, age 22.60 ± 1.50 yrs., body height 181.53 ± 6.11 cm, body weight 76.89 ± 7.30 kg). Inspiratory vital capacity (IVC), forced expiration volume (FEV1), FEV1/IVC ratio, maximal oxygen consumption (VO2max), ventilatory threshold (VO2VT) and time to exhaustion, were measured in all subjects. Student T-test for independent Sample and Cohen’s d as the measure of the effect size were calculated.

Results: Recreational basketball-engaged students (EG) reached significantly greater IVC (t = 7.240, p < 0.001, d = 1.854), FEV1 (t = 10.852, p < 0.001, d = 2.834), FEV1/IVC ratio (t = 6.370, p < 0.001, d = 3.920), maximal oxygen consumption (t = 9.039, p < 0.001, d = 3.310), ventilatory threshold (t = 9.859, p < 0.001, d = 3.607) and time to exhaustion (t = 12.361, p < 0.001, d = 4.515) compared to UG.

Conclusions: Long-term exposure to recreational basketball leads to adaptive changes in aerobic and respiratory parameters in male university students.

Associations of Sex Hormones and Hormonal Status With Arterial Stiffness in a Female Sample From Reproductive Years to Menopause

OBJECTIVE

Loss of sex hormones has been suggested to underlie menopause-associated increment in cardiovascular risk. We investigated associations of sex hormones with arterial stiffness in 19-58-years-old women. We also studied associations of specific hormonal stages, including natural menstrual cycle, cycle with combined oral contraceptives (COC) and menopausal status with or without hormone therapy (HT), with arterial stiffness.

METHODS

This study includes repeated measurements of 65 healthy women representing reproductive (n=16 natural, n=10 COC-users) and menopause (n=5 perimenopausal, n=26 postmenopausal, n=8 HT-users) stages. Arterial stiffness outcomes were aortic pulse wave velocity (PWVao) and augmentation index (AIx%) assessed using Arteriograph-device. Generalized estimating equation models were constructed to investigate associations of each hormone (wide age-range models) or hormonal stage (age-group focused models) with arterial stiffness. PWVao models with cross-sectional approach, were adjusted for age, relative fitness, fat mass and mean arterial pressure, while models with longitudinal approach were adjusted for mean arterial pressure. AIx% models used the same approach for adjustments and were also adjusted for heart rate.

RESULTS

Negative and positive associations with arterial stiffness variables were observed for estradiol and follicle-stimulating hormone, respectively, until adjustment for confounding effect of age. In naturally menstruating women, AIx% was higher at ovulation (B=3.63, p<0.001) compared to the early follicular phase. In COC-users, PWVao was lower during active (B=-0.33 - -0.57, p<0.05) than inactive pills. In menopausal women, HT-users had higher PWVao (B=1.43, p=0.03) than postmenopausal non-HT-users.

CONCLUSIONS

When using wide age-range assessments covering reproductive to menopausal lifespan it is difficult to differentiate age- and hormone-mediated associations, because age-mediated influence on arterial stiffness seemed to overrule potential hormone-mediated influences. However, hormonal status associated differentially with arterial stiffness in age-group focused analyses. Thus, the role of sex hormones cannot be excluded. Further research is warranted to resolve potential hormone-mediated mechanisms affecting arterial elasticity.

Associations of cardiorespiratory fitness, adiposity, and arterial stiffness with cognition in youth

Purpose

To investigate the associations of cardiorespiratory fitness, adiposity, and arterial stiffness with cognition in 16‐ to 19‐year‐old adolescents.

Methods

Fifty four adolescents (35 girls; 19 boys) participated in the study. Peak oxygen uptake (V̇O_2peak) and peak power output (W_max) were measured by the maximal ramp test on a cycle ergometer and ventilatory threshold (VT) was determined with ventilation equivalents. Lean mass (LM) and body fat percentage (BF%) were measured using a bioelectrical impedance analysis. Aortic pulse wave velocity (PWVao) and augmentation index (AIx%) were measured by a non‐invasive oscillometric device. Working memory, short term memory, visual learning and memory, paired‐associate learning, attention, reaction time, and executive function were assessed by CogState tests.

Results

V̇O_2peak/LM (β = 0.36 p = .011) and W_max/LM (β = 0.30 p = .020) were positively associated with working memory. W_max/LM was also positively associated with visual learning (β = 0.37, p = .009). V̇O₂ at VT/LM was positively associated with working memory (β = 0.30 p = .016), visual learning (β = 0.31 p = .026), and associated learning (β = −0.27 p = .040). V̇O₂ at VT as % of V̇O_2peak, BF%, PWVao, and AIx% were not associated with cognition.

Conclusion

Cardiorespiratory fitness was related to better cognitive function, while BF% and arterial stiffness were not associated with cognition in adolescents.

Associations of cardiorespiratory fitness, physical activity, and BMI with arterial health in middle-aged men and women

We investigated the associations of cardiorespiratory fitness (CRF), physical activity (PA) with regard to aerobic and resistance training, and body mass index (BMI) with pulse wave velocity (PWV) and augmentation index (AIx) in middle-aged adults with at least one cardiovascular risk factor. A total of 84 (46 men and 38 women) participated in the study. Cardiorespiratory fitness was measured using a maximal graded exercise test on a cycle ergometer and was defined as maximal power output (Wmax ) normalized for body weight-0.35 . Participation in aerobic and resistance training was assessed by a detailed questionnaire and BMI was calculated as weight (kg)/[height (m2 )]. Pulse wave velocity and AIx were measured using an applanation tonometry before (pre), immediately after (post), and after 10 min (post10) of maximal exercise test. Cardiorespiratory fitness, PA, or BMI was not associated with PWV or AIx. Pulse wave velocity decreased significantly from pre to post10 among those in the highest third of CRF (mean difference=-0.793 m/s, 95% CI = -1.494 to -0.091, p = .023) and in normal weight participants (p = .084 for time*group interaction mean difference=-0.781 m/s, 95% CI = -1.496 to -0.066, p = .029), but not among those in the other thirds of CRF or overweight or obese participants. Participants who had regular resistance training had continuously higher AIx from pre to post10 than those who had no regular resistance training (mean difference = -1.98, 95% CI = -4.02 to 0.069, p = .058). In conclusion, exercise may decrease PWV and AIx. Our results suggest that positive arterial responses to exercise could be slightly improved in fit and normal weight individuals.

Associations of Cardiorespiratory Fitness and Adiposity With Arterial Stiffness and Arterial Dilatation Capacity in Response to a Bout of Exercise in Children

Purpose: To investigate the associations of directly measured peak oxygen uptake ( V˙O2peak ) and body fat percentage (BF%) with arterial stiffness and arterial dilatation capacity in children. Methods: Findings are based on 329 children (177 boys and 152 girls) aged 8-11 years. V˙O2peak was assessed by a maximal cardiopulmonary exercise test on a cycle ergometer and scaled by lean body mass (LM). BF% and LM were measured by bioelectrical impedance. Stiffness index (measure of arterial stiffness) and change in reflection index (ΔRI, measure of arterial dilatation capacity) were assessed by pulse contour analysis. Data were analyzed by linear regression models. Results:V˙O2peak/LM was positively associated with ΔRI in boys adjusted for age and BF% (β = 0.169, P = .03). Further adjustments for systolic blood pressure, heart rate, and the study group had no effect on this association, but additional adjustment for clinical puberty attenuated it (β = 0.171, P = .07). BF% was inversely related to ΔRI in boys adjusted for age and V˙O2peak/LM (β = -0.171, P = .03). V˙O2peak or BF% was not associated with ΔRI in girls or with stiffness index in either boys or girls. Conclusion: Increasing cardiorespiratory fitness and decreasing adiposity may improve arterial health in childhood, especially among boys.

Arterial Stiffness and Its Relationship to Cardiorespiratory Fitness in Children and Young Adults with a Fontan Circulation

There are no previous studies on arterial stiffness and its associations with cardiorespiratory fitness in young Fontan patients. Therefore, we examined the arterial stiffness and its relationship to cardiorespiratory fitness in children and young adults with a Fontan circulation. Altogether, 17 Fontan patients and 26 healthy controls (16 females and 27 males aged 8-40 years) participated in this cross-sectional study. The cardiorespiratory fitness was assessed by cardiopulmonary exercise testing on a cycle ergometer and was defined as the standard deviation scores (SDS) of peak oxygen uptake per body mass (VO_2peak/kg) based on the national reference values and assessed with cardiopulmonary exercise testing on a cycle ergometer. Aortic pulse wave velocity (PWV_ao) as a measure of arterial stiffness and aortic Augmentation Index (AIX) as a measure of peripheral arterial tone, were assessed by non-invasive oscillometric device from upper arm. Body adiposity was determined by body mass index SDS and the sport participation by interview. Data were analyzed using linear regression analyses and Pearson's correlations, adjusted for age and sex. Fontan patients had a lower VO_2peak/kg-SDS (- 2.69 vs 0.078), higher PWV_ao-SDS (1.13 vs - 0.24) and higher AIX (19.26% vs 8.49%) in comparison with healthy controls. PWV_ao and AIX were negatively associated with VO_2peak/kg (standard regression coefficient (β) - 0.525, 95% confidence interval (CI) - 0.722 to - 0.227, p < 0.01 and β - 0.371, 95% CI - 0.672 to - 0.080, p = 0.014). Young Fontan patients have the arterial stiffness of healthy people who are twice as old. Thereby, children and young adults with a Fontan circulation have a lower cardiorespiratory fitness and less sport participation. Arterial stiffness is inversely associated with cardiorespiratory fitness and exercise training might be an intervention to improve vascular health in this population.