The effects of yoga and quiet rest on subjective levels of anxiety and physiological correlates: a 2-way crossover randomized trial

Abstract Background Rest or acute exercise can decrease state anxiety, with some evidence showing exercise to prevent laboratory-induced elevations in anxiety. No study has examined whether yoga provides short-term protection against laboratory-induced anxiety. The aim of this study was to examine the effectiveness of an acute YogaFit session on state anxiety and measures of heart rate variability (HRV) to determine whether yoga provides short-term protection against emotional picture stimuli. Methods A randomized repeated-measures crossover clinical trial was performed. Forty healthy, female college students completed a 30 min session of YogaFit and a time-matched seated rest condition on separate days. After each condition, participants viewed 30 min of emotional picture stimuli. State anxiety, heart rate and time-domain and frequency-domain measures of HRV were assessed baseline, post- condition, and post-exposure to emotional stimuli. Data were analysed using a condition x time (2 × 3) repeated-measures ANOVA. Results Post-hoc comparisons indicate the following: (1) state anxiety significantly decreased from baseline to post-condition for both yoga and rest (p = 0.001) but returned to baseline values following exposure to emotional stimuli (p < 0.001) for both conditions; (2) heart rate decreased post-condition to post-exposure (p = 0.020) and baseline to post-exposure (p = 0.033) for both conditions; (3) time-domain measure of HRV showed a significant increase in HRV between baseline and post-condition (p = 0 .019), post-condition and post-exposure (p = 0 .007), and between baseline and post-exposure (p < 0.001). Conclusions Both YogaFit and seated rest were effective at acutely reducing state anxiety post-condition, but not at preventing an induced anxiety response post-exposure. Following exposure to the emotionally stimulating pictures, there was a shift from the high frequency-domain to the low frequency-domain and an increase in the time-domain measure of HRV for both the YogaFit and the quiet rest condition. Trial registration Retrospectively registered 2/16/2018, clinicaltrials.gov, Identifier: NCT03458702

Exercise prescription and pregnancy

No data (2014)UE

Effects of high-intensity resistance training on circulating levels of irisin in healthy adults: A randomized controlled trial

Background: Existing research suggests that irisin increases in response to exercise in humans. However, results are controversial and a majority of the studies lack a control group. The present study aimed to analyze the effects of both one-bout, and three-week intense resistance training on physical fitness (body composition and strength) and serum irisin levels when compared to a control group. Methods: A total of 26 healthy young adults (n=14 males; 12 females) completed the pre-assessment phase, and were randomly assigned to either intervention or control group. Physical activity, diet, and physical fitness [strength, cardiorespiratory fitness, and body composition] were assessed. Blood samples were collected at baseline, during and post one-bout of exercise, and baseline on sessions 1, 3, 6 and 9 of 3-week high intensity resistance training (3 times per week). Results. None of the ANOVA effects on irisin concentration were significant after one-bout of exercise or 3 weeks of resistance training. The intervention group showed large significant changes from pre to post in relative body fat (%BF) (t[13]=-3.37, p=0.003), and lean body mass (p=0.016, d=0.72). All muscle strength variables [1RM bench press (F[1,22]=19.54, p<0.001, <0.01); 1RM leg press (F[1,22]= 20.84, p<0.001, =0.03); bench press-to-body weight ratio (F[1,22]=18.93, p<0.001, =0.01); leg press-to-body weight ratio (F[1,22]=23.03, p<0.001, =0.05)] showed significant group by time interaction effects. Conclusions. Serum irisin concentrations did not change during or post one-bout, nor during three-weeks of high-intensity resistance training compared to matched controls, while the program elicited significant changes in body composition and muscle strength in a group of healthy young adults. Additionally, no significant associations were found between irisin levels and physical activity, diet, or physical fitness. However, negative associations were found between baseline serum irisin concentrations and body composition (body weight and skeletal muscle mass) in males. Key words: irisin, high-intensity, resistance training, strength, body composition. Implications: There is still disagreement about the real effects of exercise on irisin levels, and the expected outcomes for different populations (i.e. young adults, elder, active, sedentary, etc.). Our randomized control trial study helped clarify the potential effects of acute and longer-term high intensity exercise on plasma irisin concentrations when compared to a control group. With this randomized controlled trial, researchers would have a reliable source about the proposed effects of resistance training interventions targeting irisin