GABA Supplementation, Increased Heart-Rate Variability, Emotional Response, Sleep Efficiency and Reduced Depression in Sedentary Overweight Women Undergoing Physical Exercise: Placebo-Controlled, Randomized Clinical Trial.

Gamma-aminobutyric acid (GABA) serves as a pivotal neurotransmitter implicated in the pathogenesis of stress, anxiety, sleep-related disorders, and heart rate (HR) reactions. Heart-rate variability (HRV), modulated by the sympathetic and parasympathetic branches of the autonomic nervous system (ANS), offers insights into cardiac autonomic control and cardiovascular well-being. The present study aimed to explore the impact of GABA supplementation on emotional metrics, sleep quality, and HRV in sedentary women with overweight or obesity partaking in physical exercise. A randomized, double-blind, placebo-controlled clinical trial was undertaken involving 30 sedentary women with overweight or obesity. Volunteers were assigned randomly to two groups: the intervention group receiving GABA (200 mg) once daily for a total of 90 supplementation doses, and the placebo group. Both groups engaged in physical exercise, while the supplementation regimen spanned 90 days. Assessments were conducted at three intervals: baseline (T0), midway through the study (T45), and study culmination (T90). Following 90 days of GABA supplementation, the intervention group demonstrated enhancements in habitual sleep efficiency, as indicated by reductions in Pittsburgh Sleep Quality Index (PSQI) scores. Moreover, an improved emotional response was observed, characterized by diminished negative affect. GABA supplementation yielded ameliorations in depression scores as per the Depression, Anxiety, and Stress Scale (DASS-21). Notably, an augmented HRV was noted, attributed to heightened parasympathetic autonomic nervous system predominance. GABA supplementation elicited noteworthy enhancements in heart rate variability, emotional response, depression mitigation, and sleep efficiency following a 90-day supplementation.

Sucrose-Sweetened Drinks Reduce the Physical Performance and Increase the Cardiovascular Risk in Physically Active Males.

INTRODUCTION: The intake of sugar-sweetened beverages (SSBs) has increased rapidly, but the effects of this habit on health and physical performance are unknown. This study assessed the effect of excessive SSB intake on biochemical, physical performance, and biochemical and cardiovascular parameters of physically active males. METHODS: Seventeen volunteers consumed a placebo drink (Pd; carbohydrate free) and an excessive SSB drink (eSSBd = Pd plus 300 g sucrose). In a blind randomized crossover study, the subjects were assigned to Pd or eSSBd groups for 15 days. After an interval of 7 days, subjects were reassigned to the other condition. RESULTS: After eSSBd intake, there was an increase in weight (69.34 ± 13.71 vs. 70.62 ± 14.06), body mass index (24.49 ± 4.01 vs. 24.97 ± 4.13), waist circumference (75.33 ± 11.22 vs. 76.79 ± 11.51), VLDL (19.54 ± 9.50 vs. 25.52 ± 11.18), triglycerides (78.94 ± 23.79 vs. 114.77 ± 43.65), and peak systolic blood pressure (178.57 ± 26.56 vs. 200.71 ± 24.64). The cardiorespiratory response to exercise (VO2max) (48.15 ± 10.42 vs. 40.98 ± 11.20), peak heart rate (186.64 ± 8.00 vs. 179.64 ± 6.28), total exercise time (15.02 ± 1.57 vs. 14.00 ± 2.18), and mechanical work (15.83 ± 4.53 vs. 13.68 ± 5.67) decreased after eSSBd intake (all values expressed in initial mean ± DP vs. final). The rates of perceived exertion were higher (1.300 vs.1.661 slope and -0.7186 vs. -1.118 y-intercept) after eSSBd intake. CONCLUSION: The present study shows that 15 days of eSSBd intake may negatively modulate biochemical parameters associated with cardiovascular risk. In addition, this overintake can impair the physical performance and cardiovascular responses to physical exercise.

Acute volume expansion decreased baroreflex response after swimming but not after running exercise training in hypertensive rats.

Background: Physical training (ET) is important to restore the reflex sensitivity involved in controlling blood pressure in various diseases. Recent investigations have demonstrated an interaction between cardiopulmonary baroreceptors and arterial baroreflex during dynamic exercise.Objective: Considering that acute and chronic hemodynamic responses to swimming (SW) are different from the race (RUN), the objective of this study was to evaluate the effect of SW and RUN on baroreflex response before and after acute volume expansion in spontaneously hypertensive rats (SHR).Methods: SHR were divided into three groups: RUN, SW and sedentary (SED) groups. After training, the mean arterial pressure (MAP) and heart rate (HR) were recorded. Baroreflex response was assessed before and after acute volume expansion.Results: Both ET conditions reduced basal levels of HR and MAP. The first volume of injected isotonic saline solution (1.25% of body weight) produced a greater decrease in HR for the SW group (-105.8 ± 8.7 bpm) compared to RUN groups (-68 ± 5.2 bpm) and SED (-49.8 ± 7.2 bpm). Both training modalities increase the baroreflex response in relation to the SED group, but after the total volume expansion, the SW group presented attenuated response (0.7 ± 0.1 µPIms/mmHg) compared to RUN (1.5 ± 0.17 PIms/mmHg) and was not different from SED group (0.8 ± 0.2 mPIms/mmHg).Conclusion: The results show that the swim-trained group has a different baroreflex response to that observed by the run-trained group after the activation of the load receptors by saline expansion.