Acute effects of Bikram yoga on ambulatory blood pressure

PURPOSE: The primary purpose of this study was to determine the acute effects of Bikram yoga on 24-hour ambulatory blood pressures (ABP) by comparing measures on a Bikram yoga (BY) day to a non-Bikram yoga (NBY) day. A secondary purpose was to investigate the effects of Bikram yoga on state anxiety and perceived stress. Measures were done to relate differences in ambulatory blood pressures between NBY and BY days with perceived stress, initial resting blood pressure, and Bikram yoga experience. METHODS: Sixteen healthy normotensive and prehypertensive subjects (M = 46.3, SD = 12.4 yr) were randomized and counterbalanced to repeat (1 week apart) two conditions of 24-hour ABP monitoring following BY and NBY control, which was ≥ 48-hours after the last bout of yoga. Subjects completed the State Trait Anxiety Inventory (STAI) before and after the BY session, and the Perceived Stress Scale (PSS) after both 24-hour ABP monitoring conditions. RESULTS: Factorial ANOVAs were used to analyze differences in ambulatory systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) on BY versus NBY days across daytime (1200-2200 h), nighttime (2200-0600 h), and next day (0600-1200 h) time periods. The M ± SE for SBP was significantly lower on BY versus NBY days for daytime (131 ± 4 vs 144 ± 3 mm Hg) and nighttime (115 ± 3 vs 122 ± 3 mm Hg) time periods, but not for next day (126 ± 3 vs 131 ± 3 mm Hg) time period. DBP was significantly lower for BY versus NBY days for daytime (80 ± 2 vs 86 ± 3 mm Hg), nighttime (64 ± 2 vs 69 ± 2 mm Hg), and next day (74 ± 3 vs 81 ± 2 mm Hg) time periods. MAP was significantly lower for BY versus NBY days for daytime (97 ± 3 vs 106 ± 3 mm Hg), nighttime (81 ± 2 vs 87 ± 2 mm Hg), and next day time (92 ± 3 vs 98 ± 3 mm Hg) time periods. Paired t-tests revealed that state anxiety was significantly lower after Bikram yoga (24.7 ± .9), than before Bikram yoga (31.9 ± 2.5); perceived stress was not significantly different over the 24-hour ABP measurement period between BY (6.3 ± .9) and NBY (7.7 ± 1.3) days. No significant correlations were found between differences in 24-hour ABP between the BY and NBY days and perceived stress, initial resting blood pressure, or Bikram yoga experience. CONCLUSION: Bikram yoga may be an effective alternative to traditional forms of exercise in reducing ABP in normotensive and prehypertensive individuals, with effects persisting across 24 hours.