The Physical Capacity of Rowing Athletes Cannot Reverse the Influence of Age on Heart Rate Variability during Orthostatic Stress.

The current study was undertaken to test the hypothesis that the high physical capacity of rowing athletes may not reverse the influence of age on cardiac autonomic control decline estimated by heart rate variability (HRV). Forty-four male subjects divided in four groups: 11 young athletes (YA; 18 ±1 year), 11 young non-athletes (YNA; 20 ±1 year), 11 middle age athletes (MAA; 43 ±6 years) and 11 middle age non-athletes (MNA; 44 ±8 years) participated in the study. Heart rate (HR) was recorded beat-by-beat for 10 minutes in supine (SUP) and 10 min in orthostatic (ORT) positions. HRV was analyzed in the frequency domain to obtain the spectral power in the high (HF) and low frequency (LF) bands, and the changes to ORT (%∆HRV) were calculated (ORT - SUP / SUP). During SUP, HF was lower in MNA and MA compared to YA and YNA, while LF was lower in MNA than YA. For %ΔHRV, %ΔHF was higher in YA than YNA, MA and MNA. The %ΔLF was not different among groups. In conclusion, aging seems to overcome the influence of physical fitness on neural regulation of the heart, as highlighted by the HRV response to active standing.

Validity of an Interval Taekwondo-Specific Cardiopulmonary Exercise Test.

ABSTRACT: Araujo, MP, Soares, PP, Hausen, MR, Julio, HS, Porto, F, and Gurgel, JL. Validity of an interval taekwondo-specific cardiopulmonary exercise test. J Strength Cond Res 35(7): 1956-1963, 2021-The objective of this study is to propose and validate an interval taekwondo-specific cardiopulmonary exercise test (ITKDtest) and compare it with running cardiopulmonary exercise test (CPET) and a continuous taekwondo-specific cardiopulmonary exercise test (CTKDtest). Fifteen athletes (age 22 ± 4 years; body mass 71.1 ± 10.2 kg; height 178.14 ± 8.3 cm; and body mass index 22.4 ± 2.4 kg·m-2) performed CPET, CTKDtest, and ITKDtest on a counterbalanced order. Oxygen uptake (V̇o2), heart rate (HR), and ventilatory thresholds (VTs 1 and 2) were measured during the 3 tests. ITKDtest started at 30 kicks per minute and increased 10 kicks each 2 minutes, with a period of passive recovery, lasting 1 minute. Interval protocol design simulated the temporal structure of an official taekwondo fight. Significant difference between specific tests was found for V̇o2 VT1 (p = 0.03), V̇o2 VT1 (%V̇o2peak) (p = 0.009), V̇o2 VT2 (p = 0.005), and V̇o2 VT2 (%V̇o2peak) (p = 0.013). Reliability was considered "excellent" for V̇o2peak (α = 0.902; SEM = 0.179), "good" for V̇o2 VT1 (α = 0.708; SEM = 3.823) and HRpeak (α = 0.803; SEM = 2.987), and "fair" for V̇o2 VT2 (α = 0.659; SEM = 4.498) and HR VT2 (α = 0.580; SEM = 8.868). Bland-Altman analyses reported a mean difference of 2.9 ± 6.6 ml·kg-1·min-1 (CPET-ITKDtest) and 1.4 ± 6.1 ml·kg-1·min-1 (CTKDtest-ITKDtest). ITKDtest may be used for measurement of cardiorespiratory variables commonly used in exercise prescription, whereas CTKDtest seems to be a more appropriate method to assess V̇o2 and HR at VTs.

Influence of breathing patterns and orthostatic stress on postural control in older adults.

AIM: To investigate the influence of breathing patterns and blood pressure behavior postural control in older adults. METHODS: A total of 20 older adults carried out spontaneous, controlled (15 cycles/min) and deep (6 cycles/min) breathing trials, in random order. In this session, the heart rate was recorded continuously and blood pressure measured every 3 min. In addition, the challenge from sitting to an active standing position was carried out with eyes closed during 6 min on a baropodometer plate with electromyography recording. The root mean square (RMS) of electromyography was calculated. RESULTS: There were significant differences in the postural control with spontaneous breathing from the first minute (center of pressure [COP]-area 216.40 ± 116.70 mm2 ) in comparison with the third minute (COP-area 79.35 ± 68.11 mm2 ; d = 0.89; P < 0.01) and the sixth minute (COP-area 70.24 ± 41.26 mm2 ; d = 0.60; P < 0.05) of active standing. Furthermore, deep breathing significantly increases the COP-area (158.50 ± 126.2 mm2 ) at the sixth minute of active standing in comparison with spontaneous breathing (70.24 ± 41.26 mm2 ; d = 0.80; P < 0.01). There were also significant differences in systolic blood pressure during spontaneous breathing between the baseline measures (sitting position 123 ± 11 mmHg) and the first minute of active standing (117 ± 13 mmHg; d = 0.24; P < 0.05). Furthermore, electromyography activity of the tibialis anterior increased during the deep (17.52 ± 9.21 RMS) and controlled breathing (16.75 ± 5.26 RMS) compared with the spontaneous condition (14.93 ± 5.56 RMS; d = 0.17; P < 0.05). CONCLUSIONS: The present data provide important insight into the respiratory and hemodynamics effects of postural control in older adults. The current data confirm that deep breathing causes periodic perturbation in the neuromuscular compensation of the lower limbs. Geriatr Gerontol Int 2018; 18: 692-697.

Proposal of a New Specific Cardiopulmonary Exercise Test for Taekwondo Athletes.

The objective of this study is to evaluate the cardiorespiratory variables of Taekwondo athletes while performing incremental exercise test on an ergometer using a ramp protocol and to propose a specific protocol for assessing these physiological variables during Taekwondo practice. Fourteen athletes participated in 2 incremental exercise tests: a treadmill exercise test (TREADtest) and a Taekwondo-specific exercise test (TKDtest). The TKDtest consists in 1-minute stages of kicks with an incremental load between then. The subjects perform kicks each time a sound signal was heard. Heart rate (HR), oxygen uptake (V[Combining Dot Above]O2), and their reserve correspondents (V[Combining Dot Above]O2R and reserve heart rate [HRR]) were divided into quartiles to verify their kinetics along the tests. Significant difference between 2 tests was found only for V[Combining Dot Above]O2R (p = 0.03). Regarding the quartiles, significant differences were found for HR in the first (p = 0.030) and second (p = 0.003). Analyzing the regression curves, significant differences were found for HR for intercept (p = 0.01) and slope (p = 0.05) and HRR for slope (p = 0.02). Analysis showed that significant reliability, with intraclass correlation coefficient (ICC), was found for the V[Combining Dot Above]O2peak (ICC = 0.855, p = 0.003), V[Combining Dot Above]O2 in ventilatory thresholds 1 (ICC = 0.709, p = 0.03) and 2 (ICC = 0.848, p = 0.003). Bland-Altman analyses reported a mean difference ± the 95% limits of agreement of 2.2 ± 8.4 ml·kg·min to V[Combining Dot Above]O2peak. The TKDtest is reliable for measurement of cardiorespiratory variables, and the behavior of these variables differs mainly from TREADtest, probably because of the motor task performed.

Correlation between cardiac autonomic modulation in response to orthostatic stress and indicators of quality of life, physical capacity, and physical activity in healthy individuals.

Increased heart rate variability (HRV) at rest is frequently associated to maximal oxygen uptake (VO2max), physical activity, and markers of quality of life (QoL). However, the HRV has not been observed during physical exercise or orthostatic (ORT) challenge. This study investigated the associations of HRV changes (ΔHRV) from rest at supine (SUP) to ORT positions with (VO2max), physical activity level, and QoL in young adults. Cardiac autonomic modulation was assessed by spectral analysis of R-R time series measured from SUP to ORT positions in 15 healthy volunteers (26 ± 7 years). Questionnaires were applied for evaluation of QoL (SF-36 score), to estimate (VO2max), and to quantify physical activity (Baecke Sport Score). All HRV indices at SUP, but not ORT, strongly correlated to QoL, estimated (VO2max), and physical activity. The ΔHRV from SUP to ORT showed significant correlations with all questionnaire scores (r = 0.52-0.61 for low frequency and r = -0.61 to -0.65 for high frequency, p ≤ 0.05). Higher vagal activity at rest and greater changes in adrenergic and parasympathetic modulation from SUP to ORT were detected in the volunteers exhibiting higher scores of QoL, estimated (VO2max), and physical activity. Taken together, the level of neural adaptations from resting SUP position to active standing, and physical activity and QoL questionnaires seem to be a simple approach to understand the physiological and lifestyle adaptations to exercise that may be applied to a large sample of subjects in almost any sports facilities at a low cost.

Prefrontal cortex transcranial direct current stimulation associated with aerobic exercise change aspects of appetite sensation in overweight adults.

This study investigated whether transcranial direct current stimulation (tDCS) on dorsolateral prefrontal cortex (DLPFC) isolated or combined with aerobic exercise influenced the desire to eat, hunger, and satiety in overweight subjects. Nine volunteers underwent anodal or sham tDCS (2 mA; 20 min) over DLPFC and isocaloric exercise bouts (70%VO(2)R; ~200 kcal). The appetite sensations were evaluated by visual analogue scales at four moments: I - Baseline; II - After tDCS; III - Post-Exercise and IV - 30-min Post-Exercise. The tDCS on left DLPFC decreased the desire to eat at baseline (tDCS -26% vs. -14% Sham). The tDCS associated with exercise had greater suppressing effect in desire to eat compared to either tDCS or exercise alone (tDCS -39% vs. -27% Sham). Moreover, the tDCS associated with exercise decreased hunger (tDCS -48% vs. 36% Sham) and increased satiety (tDCS 28% vs. 7% Sham) immediately after exercise. The post-exercise 30-min recovery elicited an overall increase in appetite. However the increase in desire to eat and hunger after recovery was lower after tDCS (29% and 13%, respectively) compared to sham stimulation (77% and 113%, respectively). These findings in overweight subjects indicate that the combination of tDCS over DLPFC and aerobic exercise induced greater decrease in appetite sensations compared to anodal tDCS or exercise alone.