Yoga improves immunosuppression after a prolonged intense exercise

Purpose: This study aimed to determine the effects of yoga on the recovery of the cardiac autonomic nervous system and immunosuppression after intense exercise. Methods: Seven healthy adult men were enrolled in two trials: rest for 30 min in a seated position (CON) and yoga for 30 min (YOG) after a treadmill running for 60 min at 75% V˙ O2max in a randomized crossover design. Natural killer (NK) cell activity, salivary secretory immunoglobulin A (SIgA), cortisol, testosterone, and indicators related to heart rate variability, mood states, and muscle soreness were measured before exercise (Pre), immediately (P0) and 60 min (P1) after rest or yoga, and the following morning (P2). Results: NK cell activity was significantly decreased in the CON trial (P < 0.05) but not in the YOG trial. The decrease in NK cell activity from Pre at P0, P1, and P2 in the CON trial was significantly larger than that in the YOG trial (P < 0.05). Testosterone secretion rate tended to be higher after yoga than at rest (P = 0.052). The square root of the mean squared difference of successive normal-to-normal intervals (RMSSD) at P0 in the YOG trial was significantly higher than that in the CON trial (P < 0.05). Changes in NK cell activity correlated with changes in RMSSD (r = 0.445, P < 0.05). Conclusion: This study showed that yoga can alleviate the decline of NK cell activity after intense exercise by enhancing parasympathetic nerve activity, thus suggesting that yoga may be an effective recovery method for athlete conditioning.