Search results for "VARIABILITY"

Monitoring stress and recovery states: Structural and external stages of the short version of the RESTQ sport in elite swimmers before championships

2016

Background: Psychological stress and recovery monitoring is a key issue for increasing athletes' health, well-being, and performance. This multi-study report examined changes and the dose–response relationships between recovery–stress psychological states, training load (TL), heart rate (HR), heart rate recovery (HRR), and heart rate variability (HRV) while providing evidence for the factorial validity of a short French version of the Recovery–Stress Questionnaire for Athletes (RESTQ-36-R-Sport). Methods: Four hundred and seventy-three university athletes (Study 1), 72 full expert swimmers (Study 2), and 11 national to international swimmers (Study 3) participated in the study. Data were an…

Smokeless tobacco, sport and the heart

2014

SummarySmokeless tobacco (snuff) is a finely ground or shredded tobacco that is sniffed through the nose or placed between the cheek and gum. Chewing tobacco is used by putting a wad of tobacco inside the cheek. Smokeless tobacco is widely used by young athletes to enhance performance because nicotine improves some aspects of physiology. However, smokeless tobacco has harmful health effects, including cardiovascular disorders, linked to nicotine physiological effects, mainly through catecholamine release. Nicotine decreases heart rate variability and the ventricular fibrillation threshold, and promotes the occurrence of various arrhythmias; it also impairs endothelial-dependent vasodilation…

The Role of Heart Rate on the Associations Between Body Composition and Heart Rate Variability in Children With Overweight/Obesity: The ActiveBrains …

2019

The authors would like to thank all the participants who volunteered for this investigation. This work is the part of a Ph.D. Thesis conducted in the Biomedicine Doctoral Studies of the University of Granada, Spain.

Heart Rate Is a Better Predictor of Cardiorespiratory Fitness Than Heart Rate Variability in Overweight/Obese Children: The ActiveBrains Project

2019

The authors would like to thank all the participants who volunteered for this investigation. This work is part of a Ph.D. thesis conducted in the Biomedicine Doctoral Studies of the University of Granada, Spain.

Impact of Nonstationarities on Short Heart Rate Variability Recordings During Obstructive Sleep Apnea

2017

Obstructive sleep apnea (OSA) is a sleep disorder characterized by breathing pauses due to collapse of the upper airways. During OSA the autonomic modulation, as noninvasively assessed through heart period (HP) variability, is altered in a time-varying way even though time-varying properties of HP fluctuations are often disregarded by HP variability studies. We performed a time domain analysis computed over very short epochs corresponding to the sole OSA events explicitly accounting for HP variability nonstationarities. Length-matched epochs were extracted during OSA and quiet sleep (SLEEP) in 13 subjects suffering from OSA (11 males, age 55±11, apnea-hypopnea index 44±19). Mean HP, varianc…

Effects of vigorous late-night exercise on sleep quality and cardiac autonomic activity

2011

Sleep is the most important period for recovery from daily load. Regular physical activity enhances overall sleep quality, but the effects of acute exercise on sleep are not well defined. In sleep hygiene recommendations, intensive exercising is not suggested within the last 3 h before bed time, but this recommendation has not been adequately tested experimentally. Therefore, the effects of vigorous late-night exercise on sleep were examined by measuring polysomnographic, actigraphic and subjective sleep quality, as well as cardiac autonomic activity. Eleven (seven men, four women) physically fit young adults (VO(2max) 54±8 mL·kg(-1)·min(-1) , age 26±3 years) were monitored in a sleep labor…

2021

To foster understanding in the psychopathology of patients with anorexia nervosa (PAN) at the psychological and physiological level, standardized experimental studies on reliable biomarkers are needed, especially due to the lack of disorder-specific samples. To this end, the autonomic nervous system (ANS) response to a psychosocial stressor was investigated in n = 19 PAN (BMI: 18.7 ± 3.3 kg/m2), age, and gender-matched to n = 19 healthy controls (HC; BMI: 24.23 ± 3.0 kg/m2). For this purpose, heart rate (HR) and heart rate variability (HRV) parameters were assessed in a cross-sectional study design under two experimental conditions: (1) rest and (2) stress (Trier Social Stress Test). In add…

Relationship between heart rate variability and the serum testosterone-to-cortisol ratio during military service

2009

Abstract The autonomic nervous system and circulating hormones control a stress reaction through a complex interaction. We tested the hypothesis that changes in cardiac vagal regulation may be positively associated with the serum testosterone-to-cortisol ratio during the first week of military service in 24 conscripts aged 19.0±0.3 years. Cardiac autonomic function was assessed by measuring high-frequency (HF: 0.15–0.4 Hz) and low-frequency (LF: 0.04–0.15 Hz) power spectral indices of R-R intervals during supine rest and during a controlled standing condition (5 min for both) from the second to the seventh mornings at the beginning of military service. Blood samples were collected to analys…

2019

Objective: In two independent study arms, we determine the effects of strength training (ST) and high-intensity interval training (HIIT) overload on cardiac autonomic modulation by measuring heart rate (HR) and vagal heart rate variability (HRV). Methods: In the study, 37 well-trained athletes (ST: 7 female, 12 male; HIIT: 9 female, 9 male) were subjected to orthostatic tests (HR and HRV recordings) each day during a 4-day baseline period, a 6-day overload microcycle, and a 4-day recovery period. Discipline-specific performance was assessed before and 1 and 4 days after training. Results: Following ST overload, supine HR, and vagal HRV (Ln RMSSD) were clearly increased and decreased (small …

Slow 0.1 Hz Breathing and Body Posture Induced Perturbations of RRI and Respiratory Signal Complexity and Cardiorespiratory Coupling

2020

Objective: We explored the physiological background of the non-linear operating mode of cardiorespiratory oscillators as the fundamental question of cardiorespiratory homeodynamics and as a prerequisite for the understanding of neurocardiovascular diseases. We investigated 20 healthy human subjects for changes using electrocardiac RR interval (RRI) and respiratory signal (Resp) Detrended Fluctuation Analysis (DFA, α1RRI, α2RRI, α1Resp, α2Resp), Multiple Scaling Entropy (MSERRI1−4, MSERRI5−10, MSEResp1−4, MSEResp5−10), spectral coherence (CohRRI−Resp), cross DFA (ρ1 and ρ2) and cross MSE (XMSE1−4 and XMSE5−10) indices in four physiological conditions: supine with spontaneous breathing, stand…