The effects of nonconcurrent and concurrent relaxation training on cardiovascular reactivity to a psychological stressor

Efficacy of yoga for vasomotor symptoms: a randomized controlled trial

OBJECTIVE

This study aims to determine the efficacy of yoga in alleviating vasomotor symptoms (VMS) frequency and bother.

METHODS

This study was a three-by-two factorial, randomized controlled trial. Eligible women were randomized to yoga (n = 107), exercise (n = 106), or usual activity (n = 142), and were simultaneously randomized to a double-blind comparison of ω-3 fatty acid (n = 177) or placebo (n = 178) capsules. Yoga intervention consisted of 12 weekly 90-minute yoga classes with daily home practice. Primary outcomes were VMS frequency and bother assessed by daily diaries at baseline, 6 weeks, and 12 weeks. Secondary outcomes included insomnia symptoms (Insomnia Severity Index) at baseline and 12 weeks.

RESULTS

Among 249 randomized women, 237 (95%) completed 12-week assessments. The mean baseline VMS frequency was 7.4 per day (95% CI, 6.6 to 8.1) in the yoga group and 8.0 per day (95% CI, 7.3 to 8.7) in the usual activity group. Intent-to-treat analyses included all participants with response data (n = 237). There was no difference between intervention groups in the change in VMS frequency from baseline to 6 and 12 weeks (mean difference [yoga--usual activity] from baseline at 6 wk, -0.3 [95% CI, -1.1 to 0.5]; mean difference [yoga--usual activity] from baseline at 12 wk, -0.3 [95% CI, -1.2 to 0.6]; P = 0.119 across both time points). Results were similar for VMS bother. At week 12, yoga was associated with an improvement in insomnia symptoms (mean difference [yoga - usual activity] in the change in Insomnia Severity Index, 1.3 [95% CI, -2.5 to -0.1]; P = 0.007).

CONCLUSIONS

Among healthy women, 12 weeks of yoga class plus home practice, compared with usual activity, do not improve VMS frequency or bother but reduce insomnia symptoms.

Effects of acute stress, relaxation, and a neurogenic inflammatory stimulus on interleukin-6 in humans

Effects of three experimental manipulations: mental stress, relaxation, and a nociceptive inflammatory stimulus, capsaicin, on levels of interleukin-6 (IL-6) were examined. Fifty subjects were pre-trained in relaxation and then randomized to a stress (Stroop test), relaxation (tape), or control (video) manipulation. Subjects participated in an evening reactivity session including 20 min of stress, relaxation, or control followed by a capsaicin injection in the forearm. Cardiovascular variables and levels of IL-6 were measured before and after the manipulation, and at regular intervals up to 60 min post-capsaicin. Group assignment did not differentially affect change in IL-6 over time, either before or after capsaicin. Small but significant increases in IL-6 were seen at 60 min post-capsaicin. These findings suggest that an acute stress manipulation does not modulate IL-6 within this time frame. Although IL-6 did increase following a neurogenic inflammatory stimulus, it did so subsequent to the maximum flare, suggesting that flare mechanisms are independent of IL-6.

Can relaxation lower metaboreflex-mediated blood pressure elevations?

PURPOSE

Relaxation can lower resting blood pressure, and this investigation sought to determine whether relaxation could reduce mean blood pressure (MBP) elevations produced by postexercise circulatory occlusion (PECO).

METHODS

Sixteen volunteers trained with relaxation and were able to decrease MBP at rest by at least 5 mm Hg within 2 min. Subjects performed four tests assigned randomly: i). rest with cuff occlusion, ii). rest and cuff occlusion with relaxation, iii). hand-grip exercise followed by PECO rest with cuff occlusion, and iv) hand-grip exercise followed by PECO with relaxation. Data for HR and MBP were collected using a Finapres; ratings of relaxation and discomfort from cuff occlusion were obtained using a 1- to 10-unit scale. Stroke volume (SV) and HR were collected from six subjects to calculate cardiac output and total peripheral conductance (TPC). Dependent variables were compared using an ANOVA.

RESULTS

HR (mean +/-SD) was lower during both relaxation conditions as compared with control (-7 +/- 4 bpm vs -2 +/- 3 bpm; P< 0.05). The MBP was reduced during relaxation alone (-6 +/- 3.7 mm Hg; < 0.05) but not during PECO with relaxation. The rating of relaxation was higher during relaxation (6.8 +/- 1.3 units) versus control (3.5 +/- 1.2 units), but ratings were not different between relaxation conditions. Ratings of discomfort were higher during PECO ( P< 0.05). Relaxation did not significantly alter CO or SV (N= 6). During relaxation alone, TPC was increased (0.046 +/- 0.001 vs 0.049 +/- 0.002 L.min.mm Hg; P< 0.05). However, TPC was significantly increased during PECO with relaxation.

CONCLUSIONS

These findings suggest that although relaxation can affect cardiovascular regulation and lower HR and MBP at rest, this central signal cannot lower reflex increases in blood pressure originating from a peripheral metabolic stimulus.

Mind-body therapy in the management and prevention of coronary disease

Conventional mind-body therapy has been proven a valuable noninvasive way to manage coronary disease. Yoga practice, especially, has been found to be valuable in preventing adverse outcomes of coronary disease by improving resistance to stress.