Modulation of sleep quality, cardiac autonomic activity, and cognition by yoga in medical students

Objectives The disturbed sleep quality among medical students due to their hectic schedule may negatively impact the cognition, consequently affecting their academic performance. With the hypothesis that short duration of simple yogic exercises may improve sleep quality and heart rate variability (HRV), and thus may improve cognitive abilities, the study aims to evaluate the outcome of short duration yoga training on HRV, cognition, and sleep in medical students. Material and Methods The participants of the study were young and apparently healthy medical students. The study commenced after the Institutional Scientific Re- search and Ethics Committee approval. The informed consent was taken from all the participants in writing. All parameters (height, weight, age, body mass index [BMI], systolic blood pressure [SBP], diastolic blood pressure [DBP], heart rate [HR]) along with HRV, sleep quality (using Pittsburgh Sleep Quality Index [PSQI]), and cognitive ability (using Trail Making Tests Parts A & B [TMTs-A&B]) were assessed in the participants at baseline. Thereaf- ter, the students practiced yoga (asanas, pranayama, and meditation) under supervision of a yoga instructor and a faculty for the duration of one hour every day for six weeks. Measurements were repeated after six weeks. Depending on the normality of data and data distribution, the comparison was done using Wilcoxon Signed Rank Test or dependent samples t-test. The level of significance was kept as p < 0.05. Results Following six weeks of yoga sessions, a significant improvement in the high frequency power normalized unit (HFnu) and total power in comparison to baseline values was observed: 53.25± 10.14 versus 59.57 ± 9.61 and 3238 ± 1133 versus 3473 ± 1130, respectively. Significant difference at six weeks between baseline and post yoga values was observed in TMT-A (30.16 ± 5.04 vs 19.84 ± 2.76) and TMT-B (69.96 ± 12.99 vs 49.24 ± 10.99). Sleep quality also improved significantly after yoga sessions (baseline PSQI score of 10.68 ± 1.79 and post-PSQI score of 4.12 ± 1.67). Conclusion It was concluded that one hour of supervised yoga session every day for six weeks can improve HRV, sleep quality, and cognitive ability among medical students. Medical students should practice yoga regularly to improve cognitive function and sleep and to reduce cardiovascular morbidity.