Plain language summary
Increased stress and anxiety levels can lead to elevated cardiovascular responses and reduced capacity for stress recovery. Recent studies have found both an acute period of rest and bout of acute aerobic exercise to be effective in reducing stress, suggesting time away from stressors is what alters anxiety levels. Yoga has been reported to improve both physiological and psychological coping response to stressors, however yoga has not been studied in this context. The aim of this randomised, crossover study was to determine the effects of 30 minutes of yoga and seated rest on anxiety measures, namely heart rate variability (HRV), in forty healthy female university students. Participants were randomised to either begin with seated rest or vinyasa yoga, and after each session were shown 90 emotionally stimulating photos. Post-exposure stress and anxiety responses were measured. This study found both rest and yoga were effective for acutely reducing anxiety levels, however these positive effects did not persist after exposure to emotional stimuli. Based on these results, the authors support the theory that time away from stressors is important for reducing anxiety.
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 .
Methodological quality
Jadad score
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3
Allocation concealment
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Yes
