Obesity does not Impair Ambulatory Cardiovascular and Autonomic Responses Post-exercise.

This study aimed to assess whether obesity and/or maximal exercise can change 24 h cardiac autonomic modulation and blood pressure in young men. Thirty-nine men (n: 20; 21.9±1.8 kg·m-2, and n: 19; 32.9±2.4 kg·m-2) were randomly assigned to perform a control (non-exercise) and an experimental day exercise (after maximal incremental test). Cardiac autonomic modulation was evaluated through frequency domain heart rate variability (HRV). Obesity did not impair the ambulatory HRV (p>0.05), however higher diastolic blood pressure during asleep time (p=0.02; group main effect) was observed. The 24 h and awake heart rate was higher on the experimental day (p<0.05; day main effect), regardless of obesity. Hypotension on the experimental day, compared to control day, was observed (p<0.05). Obesity indicators were significantly correlated with heart rate during asleep time (Rho=0.34 to 0.36) and with ambulatory blood pressure(r/Rho=0.32 to 0.53). Furthermore, the HRV threshold workload was significantly correlated with ambulatory heart rate (r/Rho=- 0.38 to-0.52). Finally, ambulatory HRV in obese young men was preserved; however, diastolic blood pressure was increased during asleep time. Maximal exercise caused heart rate increase and 24h hypotension, with decreased cardiac autonomic modulation in the first hour, regardless of obesity.

Parasympathetic modulation during sleep time is reduced after maximal exercise, correlated with aerobic fitness in young women / A modulação parassimpática durante o sono é reduzida após o exercício máximo e está correlacionada com a aptidão aeróbia em mulheres jovens

abstract It is known that cardiovascular risk is increased during exercise and recovery. Thus, it is necessary to assess all the risk associated with exercise to minimize the possibility of cardiovascular events. The aim of this study was to verify whether a maximal exercise alters ambulatory cardiac autonomic modulation in untrained women and whether aerobic fitness is correlated to cardiac autonomic modulation. Twelve women (25.35 ± 5.44 years) were outfitted with the Holter monitor on an experimental (after maximum exercise) and a control day to heart rate variability (HRV) evaluation. Maximal exercise increased 24 h heart rate (82 ± 14 vs 77 ± 11 bpm; p = 0.04) and during sleep time (72 ± 14 vs. 65 ± 9 bpm; p = 0.01), reduced parasympathetic modulation (HF - n.u. 49.96 ± 11.56 vs 42.10 ± 14.98; p = 0.04), and increased low-frequency/high-frequency ratio (2.88 ± 3.24 vs 1.31 ± 0.60; p = 0.03) during sleep time compared to the control day. Aerobic fitness was correlated positively with LF, HF, and HF (n.u.) indices (r = 0.61 to 0.73, p < 0.05) and correlated negatively with LF (n.u.) and LF/HF ratio (Rho = - 0.57 to - 0.69; p < 0.05). Maximal exercise alters parasympathetic modulation during sleep time in untrained women. Ambulatory cardiac autonomic modulation after exercise is related to aerobic fitness.

resumo Sabe-se que o risco cardiovascular aumenta durante o exercício e sua recuperação. Assim, é necessário avaliar todo o risco associado ao exercício para minimizar a chance de eventos cardiovasculares. Objetivou-se verificar se um exercício máximo altera a modulação autonômica cardíaca ambulatorial em mulheres não treinadas e se a aptidão aeróbia está correlacionada à modulação autonômica cardíaca. Doze mulheres (25,35 ± 5,44 anos) foram equipadas com monitor Holter em um dia experimental (após exercício máximo) e dia controle para avaliação da variabilidade da frequência cardíaca (VFC). O exercício máximo aumentou a frequência cardíaca de 24 h (82 ± 14 vs 77 ± 11 bpm; p = 0,04) e durante o sono (72 ± 14 vs 65 ± 9 bpm; p = 0,01), bem como reduziu a modulação parassimpática (HF - nu 49,96 ± 11,56 vs 42,10 ± 14,98; p = 0,04) e aumentou a razão de baixa frequência / alta frequência - LF/HF (2,88 ± 3,24 vs 1,31 ± 0,60; p = 0,03) durante o período do sono em comparação com o dia controle. A aptidão aeróbia foi correlacionada positivamente com os índices LF, HF e HF (nu) (r = 0,61 a 0,73, p <0,05) e negativamente correlacionada com LF (nu) e razão LF / HF (Rho = - 0,57 a - 0,69; p <0,05). O exercício máximo altera a modulação parassimpática durante o sono em mulheres não treinadas. A modulação autonômica cardíaca ambulatorial após o exercício foi correlacionada com a aptidão aeróbia.

Aerobic fitness and recovery type influence post-exercise heart rate in young women / Aptidão aeróbia e tipo de recuperação influenciam a frequência cardíaca pós-exercício em mulheres jovens

This study aimed to analyze both influence of aerobic fitness and active recovery in heart rate (HR) reduction after maximum exercise (i.e. maximum incremental test) in untrained young women. Seventeen women were evaluated (23.88 ± 4.85 years), divided by the medium of peak of consumption of oxygen (30.80 mL. kg-1.min-1), in higher or lower aerobic fitness obtained during a maximum incremental test performed on a cycle ergometer. The post-exercise recovery was performed actively and passively, on two randomly non-consecutive days. It was noticed that HR at 6th and from the 6th to 10th min after the passive and active recovery, respectively, was lower in the higher aerobic fitness group, beyond that, the values of %HR reduction from the 6th to 10th min at 6th min after passive and active recovery, respectively, were higher in the higher aerobic fitness group. After active recovery, HR in 8th and 9th min and %HR reduction of the 8th to 10th min were lower and higher, respectively (p<0.05) than passive recovery in the lower aerobic fitness group. In short, the aerobic fitness influenced HR reduction after maximum exercise in untrained young women, mainly, after passive recovery. Besides that, the active recovery showed benefits in HR reduction in lower aerobic fitness group....(AU)

O presente estudo teve como objetivo analisar a influência da aptidão aeróbia e recuperação ativa na redução da frequência cardíaca (FC) após o exercício máximo (teste incremental máximo) em mulheres jovens não treinadas. Foram avaliadas dezessete mulheres jovens (23,88 ± 4,85 anos), divididas pela mediana do consumo pico de oxigênio (30,80 mL∙kg-1 ∙min-1 ), em maior ou menor aptidão aeróbia obtida durante um teste incremental máximo. A recuperação pós-exercício foi realizada de forma ativa e passiva, em dois dias experimentais randomizados e não consecutivos. Foi observado que, a FC foi menor no grupo de maior aptidão aeróbia no 6º min após a recuperação passiva e do 6º ao 10º min após a recuperação ativa, além disso, os valores do percentual de redução da FC foram maiores no grupo de maior aptidão aeróbia do 6º ao 10º min e no 6º min após a recuperação passiva e ativa, respectivamente. Após a recuperação ativa, a FC no 8º e 9º min e o percentual de redução da FC do 8º ao 10º min foram menores e maiores, respectivamente (p <0,05) do que após a recuperação passiva no grupo com menor aptidão aeróbia. Em suma, a aptidão aeróbia influenciou na redução da FC pós-exercício máximo em mulheres jovens não treinadas, principalmente após a recuperação passiva. Além disso, a recuperação ativa auxiliou na redução da FC no grupo com menor aptidão aeróbia....(AU)

Reproducibility of Heart Rate Variability Threshold in Untrained Individuals.

The aim of this study was to evaluate the reproducibility of the heart rate variability threshold (HRVT) by different HRV indexes and determination criteria. 68 untrained participants, 17 women (24.09±4.91 years old; 21.54±1.97 kg∙m-2) and 51 men (24.52±3.52 years old; 26.51±6.31 kg∙m-2), were evaluated on 2 different days (test and retest). The HRVT was determined during an incremental exercise test using 2 indexes (SD1 and RMSSD) and criteria (HRTV1, first intensity of physical effort with index<3 ms, and HRVT2, first intensity of physical effort, in which the index presents a difference<1 ms between 2 consecutive intensities). There was no significant difference (p<0.05) between the test and retest for any of the variables evaluated. All variables, except for the rate of perceived exertion at HRVT2, presented moderate to high intraclass correlation coefficient (HRVT1: 0.55-0.85 and HRVT2:0.58-0.69). All variables at HRVT1 and the heart rate at HRVT2 showed coefficient of variation ~ 10%. The HRVT, regardless of criteria and HRV index used, showed satisfactory reproducibility. Thus, these criteria can be used to assess clinically autonomic cardiac modulation and aerobic capacity, and to analyze the effect of different interventions.

Blood pressure and cardiac autonomic modulation at rest, during exercise and recovery time in the young overweight

This study aimed to assess the blood pressure (BP), cardiac autonomic modulation at rest, in physical exercise and in the recovery in untrained eutrophic (E) and overweight (O) youth. The body mass index (BMI), waist circumference (WC), systolic BP-SBP (E: 109.80 ± 10.05; O: 121.85 ± 6.98 mmHg) and diastolic BP - DBP (E: 65.90 ± 7.28; O: 73.14 ± 12.22 mmHg) were higher in overweight and the heart rate recovery (%HRR) was lower as compared with E volunteers. The BMI was associated with SBP (r= 0.54), DBP (r= 0.65), load on the heart rate variability threshold - HRVT (r= -0.46), %HRR 2' (r= -0.48) and %HRR 5' (r= -0.48), and WC was associated with SBP (r= 0.54), DBP (r= 0.64) and HRR 2' (r= -0.49). The %HRR was associated to SBP, DBP and HRVT. In summary, the anthropometric variables, BP and cardiac autonomic modulation in the recovery are altered in overweight youth.