What is the clinical evidence from this study?

Study design: Other. Intervention: Autogenic training (relaxation) vs. Quiet rest. Primary outcome: Amplitude of the high-frequency component of heart rate variability (p=0.008).

May 1, 1994

Effect of relaxation training on cardiac parasympathetic tone

Key Result

Autogenic relaxation training significantly increased the amplitude of the high-frequency component of heart rate variability compared to quiet rest (p=0.008).

Structured PICO

Does relaxation training increase cardiac parasympathetic tone as measured by heart rate variability in college students?

Population

16 college students evaluated during a 5-minute baseline followed by three 5-minute sessions of relaxation training or quiet rest.

Intervention

Autogenic training (relaxation) for three successive 5-min sessions while breathing synchronously with a visual pacemaker (0.25 Hz)

Comparator

Quiet rest (control) for the same periods while breathing synchronously with a visual pacemaker (0.25 Hz)

Outcome

Amplitude of the high-frequency component of heart rate variabilitysurrogate

Relaxation training increases the high-frequency component of heart rate variability, indicating enhanced cardiac parasympathetic tone.

Main Result

p-value: p=0.008

Abstract

To examine the hypothesis that the relaxation response is associated with an increase in cardiac parasympathetic tone, the frequency components of heart rate variability during relaxation training were investigated in 16 college students. Electrocardiograms and pneumograms were recorded during a 5-min baseline period followed by three successive 5-min sessions of the autogenic training (relaxation) or by the same periods of quiet rest (control), while subjects breathed synchronously with a visual pacemaker (0.25 Hz). Although neither the magnitude nor the frequency of respiration showed a significant difference between relaxation and control, the amplitude of the high-frequency component of heart rate variability increased only during relaxation (p = .008). There was no significant difference in the ratio of the low-frequency (0.04-0.15 Hz) to the high-frequency amplitudes. The increased high-frequency amplitude without changes in the respiratory parameters indicates enhanced cardiac parasympathetic tone. Thus, our results support the initial hypothesis of this study. Enhanced cardiac parasympathetic tone may explain an important mechanism underlying the beneficial effect of the relaxation response.

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