Resting Bradycardia, Enhanced Postexercise Heart Rate Recovery and Cardiorespiratory Fitness in Recreational Ballroom Dancers

Effects of Breakfast Omission on Resting, Exercise, and Postexercise Autonomic and Hemodynamic Profile in Men

Purpose: The acute effects of fasting interventions on metabolic dynamics have been widely investigated. However, knowledge about the acute effect of overnight fasting on hemodynamic and cardiac autonomic modulation is limited, especially during and after exercise. Our objective was to investigate the effects of breakfast omission on hemodynamic and cardiac autonomic modulation during different stress conditions. Method: Twenty-one young men [age: 20.3 (20.1, 26.5 years); body mass index: 22.7 (21.4, 24.4 kg/m²)] underwent resting and postexercise blood pressure assessments and heart rate variability (HRV) analysis, using the SD1 and SD2 indices of Poincaré plots, at rest in supine and standing positions, every 10 minutes during moderate cardiorespiratory training and every 10 minutes throughout the postexercise recovery phase, for a total of 30 minutes for each phase (exercise and recovery). All measurements were performed in a randomized order after overnight fasting or 60 minutes after a breakfast containing ~20% of the total recommended daily calories. The normality hypothesis was rejected, and the Wilcoxon test was conducted to compare the interventions (p < .05). Results: No differences between interventions were observed for resting and postexercise blood pressures (p = .21 to 0.87) or for resting, exercise, and postexercise SD1 (p = .10 to 0.82) and SD2 indices (p = .14 to 0.71). Conclusions: We concluded that overnight fasting does not promote significant changes in resting and postexercise blood pressures or cardiac autonomic modulation in young men at rest (in supine and standing positions), during 30 minutes of moderate cardiorespiratory training and throughout a 30-minute postexercise recovery phase.

Yoga, Dance, Team Sports, or Individual Sports: Does the Type of Exercise Matter? An Online Study Investigating the Relationships Between Different Types of Exercise, Body Image, and Well-Being in Regular Exercise Practitioners

Physical activity, specifically exercising, has been suggested to improve body image, mental health, and well-being. With respect to body image, previous findings highlight a general benefit of exercise. This study investigates whether the relationship between exercising and body image varies with the type of exercise that individuals preferentially and regularly engage in. In addition, physical efficacy was explored as a potential psychological mediator between type of exercise and body image. Using a cross-sectional design, healthy regular exercise practitioners of yoga, ballroom dance, team sports, or individual sports as well as healthy adults reporting no regular exercising were surveyed. Body image and its different facets were assessed by a set of standardized self-report questionnaires, covering perceptual, cognitive, and affective body image dimensions particularly related to negative body image. In addition, participants were questioned with regard to mental health. Participants were 270 healthy adults. Descriptive statistics, measures of variance (ANOVA), and multiple linear regression analysis with orthogonal contrasts were performed to investigate differences between the different exercise and non-exercise groups in the variables of interest. In line with the hypotheses and previous findings, the statistic comparisons revealed that body dissatisfaction (as one important factor of negative body image) was most pronounced in the non-exercise group compared to all exercise groups [contrast: no exercise versus exercise (all groups taken together)]. Physical efficacy, as assessed with a standardized questionnaire, mediated the difference between type of exercise (using contrasts) and body image including perceptual, cognitive, and affective body image dimensions. The findings shed light on so far less systematically investigated questions regarding the relationship between types of exercise, like yoga and ballroom dance, and body image. The results underscore the relevance of considering possible influencing factors in exercise research, such as the perception of one's physical efficacy as a mediator of this relationship.

Caffeine increases parasympathetic reactivation without altering resting and exercise cardiac parasympathetic modulation: A balanced placebo design

The sympathicotonic effect of caffeine is strongly evidenced in the literature. However, the effects of caffeine or caffeine expectancy on the cardiac parasympathetic modulation remain obscure. Thus, the aim of this study was to investigate the effects of caffeine consumption and expectancy of caffeine consumption on the cardiac parasympathetic modulation under different stress conditions. Twenty-one physically active men (22.3 ± 2.9 years, 25.2 ± 2.7 kg/m²) consumed ∼3 mg/kg of caffeine received as caffeine, caffeine as placebo, placebo as placebo and placebo as caffeine. Parasympathetic modulation was assessed by heart rate variability (HRV-Poincaré SD1 index) at supine and orthostatic positions, during a submaximal exercise (HRV threshold-HRV_T) and during each 60 seconds (s) within 300 s of post-exercise active recovery. A factorial ANOVA for repeated measures (p < 0.05) was used to assess the effect of caffeine, expectancy and resting time after caffeine intake on the HRV. No significant effect of caffeine or expectancy was observed on the SD1 value at supine or standing positions (p = 0.47-0.53; p = 0.57-0.31, respectively), despite an increase in this variable after resting periods in both positions (p < 0.001). During exercise, caffeine and expectancy do not alter the HRV_T (p = 0.51-0.39). However, higher SD1 values were observed after caffeine administration from 60 to 300 s post-exercise recovery (p = 0.01-0.05) but not for the effects of expectancy (p = 0.19-0.94). We concluded that low doses of caffeine or expectancy do not alter the resting cardiac parasympathetic modulation or HRV_T. However, caffeine, but not expectancy, increases parasympathetic reactivation after a submaximal exercise test in young men.