Table 8.

Cross-Sectional Studies and Clinical Trials Investigating the Effects of Yoga and Yoga-Based Programs on Markers of Sympathetic Activation and Reactivity, Cardiovagal Function, and Cardiovascular Recovery from Stress, Stratified by Study Design and Intervention: Summarized Findings (Studies Reporting Beneficial Effects Are in Bold)

Findings, by EndpointStudy Design
Cross-Sectional (Yoga Alone)1 to 2 Sessions (Yoga Alone)Uncontrolled Clinical Trials (>2 Sessions)Non-Randomized Controlled Clinical Trials (>2 Sessions)Randomized Controlled Trials (>2 Sessions)
Yoga AloneMultiple InterventionsYoga AloneMultiple InterventionsYoga AloneMultiple Interventions
Respiratory and Heart Rate
    Respiratory rate
        Reduced[103, 116, 139][104, 140][123]*[141]
        Unchanged[143][128]
    Heart rate (HR)
        Reduced baseline[96][145][117]† [90, 111, 116][104, 151][123]* [93][98, 145][107, 114, 115, 125–127, 141]
        Reduced during/after yogic exercise[142, 143]
        Unchanged[103][140][113][128]‡
Neuroendocrine markers
    Epinephrine/norepinephrine
        Increased plasma[147][93]
        Reduced urinary[68][120][98]
        Reduced urinary VMA[68][146]
    Cortisol
        Reduced[82][147] [158]§
        No change[110][157]
Increased excretion[89]‖[98]
    Increased basal skin resistance/reduced skin conductance[143, 145][117]†[68, 104][125, 146]
        Reduced renin activity[120, 124][102]
↓ Cardiovascular reactivity to stress
    Reduced DBP response to HGT[151]
    Reduced DBP, SBP response to CPT[152]
    Reduced DBP rise with exercise[152]
    Reduced HR rise with exercise[105][112, 153][127]
    ↓ Cardiovascular recovery time after stress
    Faster HR return to baseline after exercise[144][153]
    Faster DBP, SBP return to baseline after
        Exercise[152]
        Cold pressor test (CPT)[152]
Increased Heart rate variability
    Increased (power of mid frequency/high frequency (HF) component)[36, 143][140]†[114]
    Increased (HF component of α index)[114]
    Reduced (power of low frequency component)[143][140]†
    Increased RRIV[115]
Other measures of ↑ baroreflex sensitivity
Reduced HR, blood pressure response to head-up/head-down tilt[111][120]

  • * In both hypertensive and normotensive subjects.

  • † Only in subjects with Occupational Stress Index scores greater than the median.

  • With biofeedback.

  • ‖ 17-hydroxy-corticosteroid.

  • § Only in subjects with initial cortisol levels above the median; cortisol levels in those below the median did not change.

  • ‡ Yoga PR in addition to exercise vs. exercise alone.

  • Abbreviations: CPT, cold pressor test; DBP, diastolic blood pressure; HGT, hand grip test; HR, heart rate; RRIV, R-R (heart rate) interval variation; SBP, systolic blood pressure; VMA, vanillylmandelic acid, a metabolite of norepinephrine.