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Evaluating the Clinical Utility of Daily Heart Rate Variability Assessment for Classifying Meaningful Change in Testosterone-to-Cortisol Ratio: A Preliminary Study.
DeBlauw, JA, Crawford, DA, Kurtz, BK, Drake, NB, Heinrich, KM
International journal of exercise science. 2021;14(3):260-273
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Exercise-induced hormonal responses are controlled by the hypothalamic-pituitary adrenal axis, a key regulator of homeostasis, which responds to stress by triggering a series of endocrine changes resulting in the release of testosterone (T) and cortisol (C). The aim of this study was to determine the relationship between daily resting heart rate variability (HRV) and pre-exercise T:C ratio and evaluate the clinical utility (i.e., diagnostic validity and reliability) of daily HRV assessment in classifying atypical T:C ratio changes throughout a nine-week high-intensity functional training (HIFT) intervention. This study is a secondary analysis of a subset of participants from a larger study. Eight recreationally active men and women ages 18-35 were recruited for participation. Following 14 days of baseline HRV assessments, participants were randomized to either the treatment or control condition. Results show a statistically significant negative relationship between HRVdaily and the T:C ratio throughout 9-weeks of HIFT. Additionally, there was no significant relationship found between C and HRVdaily and neither sex nor group were significant factors. Authors conclude that their findings emphasize the potential of HRV for the guidance of training, however, as hormonal responses to training are highly individual, the creation of individual autonomic nervous systems and hormonal profiles would increase the accuracy of training stress modulation.
Abstract
The study purpose was to determine the relationship of resting heart rate variability (HRV) and testosterone to cortisol (T:C) ratio, along with the diagnostic ability of HRV to assess changes in T:C ratio during a 9-week high-intensity functional training intervention. Eight recreationally-active men (n = 4, age 24.25 ± 1.75 yrs, height 181.25 ± 3.86 cm, weight 79.68 ± 11.66 kg) and women (n = 4, age 26 ± 3.6 yrs, height 164.25 ± 3.3, weight 73.4 ± 8.42) completed daily HRV measurements (HRVdaily) using photoplethysmography via a commercially-available smartphone application along with weekly saliva samples. Saliva samples were analyzed for concentrations of testosterone (T) and cortisol (C) via enzyme-linked immunosorbent assays. Upon study completion 72 data points were available, due to participant compliance and inadequate saliva sample, 67 matched pairs of HRV and T:C ratio were analyzed. A statistically significant negative relationship (n = 67, r = -.315, p < 0.05) was found between HRVdaily and saliva T:C ratio concentrations within aggregate data. Individual participant relationships showed considerable variability (r = -0.101 - 0.665, p = 0.103 to 0.829 The model which best explained the data resulted in AIC = 130.247 with factors HRVdaily (β = -0.218, 95%CI = -0.391, -0.044, t = -2.46, p < 0.05), Sex (β = 0.450, 95%CI = -0.214, 1.114, t = 1.113, p = 0.242), and Group (β = -0.394, 95%CI = -1.089, 0.302, t = -1.11, p = 0.311). Diagnostically, HRVdaily demonstrates excellent sensitivity (95%), but poor specificity (5%) for detecting meaningful changes in T:C ratio. Assessment of HRVdaily may be a clinically valid proxy measure for monitoring hormonal changes throughout a training intervention.
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Impact of Experimentally Induced Cognitive Dietary Restraint on Eating Behavior Traits, Appetite Sensations, and Markers of Stress during Energy Restriction in Overweight/Obese Women.
Morin, I, Bégin, C, Maltais-Giguère, J, Bédard, A, Tchernof, A, Lemieux, S
Journal of obesity. 2018;2018:4259389
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The treatment of obesity has become a public health priority given the negative impact of this condition on physical and mental health. The aim of this study was to compare the effects of energy restriction alone or in combination with induced cognitive dietary restraint (CDR) on eating behaviour traits, appetite sensations, and markers of stress in overweight and obese premenopausal women. The study is a single-blinded randomised clinical study which recruited premenopausal women aged between 26 and 50 years. The participants were randomised to either an energy-restriction-plus-induced CDR condition (CDR+group) or an energy-restriction-without induced CDR condition (CDR−group). Results indicate that inducing CDR in a context of energy restriction had no further effects on eating behaviour traits, appetite sensations, and markers of stress in the short term as well as in the longer term than energy restriction alone. Authors conclude that increasing CDR has no negative impact on factors regulating energy balance in the context of energy restriction.
Abstract
Weight loss has been associated with changes in eating behaviors and appetite sensations that favor a regain in body weight. Since traditional weight loss approaches emphasize the importance of increasing cognitive dietary restraint (CDR) to achieve negative energy imbalance, it is difficult to untangle the respective contributions of energy restriction and increases in CDR on factors that can eventually lead to body weight regain. The present study aimed at comparing the effects of energy restriction alone or in combination with experimentally induced CDR on eating behavior traits, appetite sensations, and markers of stress in overweight and obese women. We hypothesized that the combination of energy restriction and induced CDR would lead to more prevalent food cravings, increased appetite sensations, and higher cortisol concentrations than when energy restriction is not coupled with induced CDR. A total of 60 premenopausal women (mean BMI: 32.0 kg/m2; mean age: 39.4 y) were provided with a low energy density diet corresponding to 85% of their energy needs during a 4-week fully controlled period. At the same time, women were randomized to either a condition inducing an increase in CDR (CDR+ group) or a condition in which CDR was not induced (CRD- group). Eating behavior traits (Three-Factor Eating Questionnaire and Food Craving Questionnaire), appetite sensations (after standardized breakfast), and markers of stress (Perceived Stress Scale; postawakening salivary cortisol) were measured before (T = 0 week) and after (T = 4 weeks) the 4-week energy restriction, as well as 3 months later. There was an increase in CDR in the CDR+ group while no such change was observed in the CDR- group (p=0.0037). No between-group differences were observed for disinhibition, hunger, cravings, appetite sensations, perceived stress, and cortisol concentrations. These results suggest that a slight increase in CDR has no negative impact on factors regulating energy balance in the context of energy restriction.