Effects of a 10-Minute Back Rub on Cardiovascular Responses in Healthy Subjects

American Journal of Chinese Medicine, Wntr, 2001 by Tommy Boone, Michelle Tanner, Angela Radosevich

(Accepted for publication July 28, 2000)

Abstract: This study determined the cardiovascular responses to a 10-minute back rub. Twelve healthy, college-age males and females (mean age = 22 years) volunteered to participate as subjects. Using an ABA design, the subjects tested for 10 minutes (Control #1) on a padded plinth lying on one side. During the Treatment period, the back rub was administered, which was followed by Control #2. Oxygen consumption ([VO.sub.2]) was determined via the Medical Graphics CPX/D metabolic analyzer, which also estimated cardiac output (Q) using the [CO.sub.2] rebreathing (equilibrium) method. A repeated measures ANOVA was performed to statistically compare the cardiovascular responses across the three periods. The back rub, when compared to Control #1, had no significant effect on [VO.sub.2], but the central and peripheral components of [VO.sub.2] were changed. Cardiac output was decreased as a result of the decreased stroke volume (SV), as a function of the increased peripheral vascular resistance (PVR). We also found an increase in the extraction of oxygen (a-v[O.sub.2] diff) in the peripheral tissues. These results indicate that the [VO.sub.2] response during the back rub was achieved by reciprocal central (SV,Q) and peripheral (a-v[O.sub.2] diff) adjustments. Following the back rub, (i.e., Control #2 vs. Treatment), the decrease in [VO.sub.2], [VCO.sub.2] [Ve, and a-v[O.sub.2] diff appears to indicate that it was effective in inducing relaxation. Since HR, SV, and Q were unchanged, the [VO.sub.2] response was a result of the decreased a-v[O.sub.2] diff. Hence, the findings suggest certain positive implications for the health care industry.

Massage is assumed to have developed from Chinese Folk medicine. By 2000 BC, its uses for healing purposes were known throughout India, Egypt, Persia, and Japan. The Greeks prescribed massage for their athletes, and Hippocrates left behind prescriptions for massage (Tappan, 1988). The benefits of massage and back rubs are said to include a decrease in pain, relaxation, and improvement in circulation. However, the physiological reports in the literature are conflicting.

Researchers report a decrease in heart rate (Madison, 1973), an increase in heart rate (Tyler et al., 1990), no change in heart rate or blood pressure (Kaufmann, 1964; Longworth, 1982; Bauer and Dracup, 1987), and a decrease in blood pressure and heart rate (Fakouri and Jones, 1987). In spite of the discrepant results, massage and back rubs are examples of touching by caregivers that is perceived as communicating care and concern (Barnett, 1972; McCorkle, 1974). Touch and back massages are postulated to bring about relaxation (Harrison, 1986; Carnahan, 1988), which is hypothesized to result in a decrease in sympathetic nervous system activity and an increase in parasympathetic activity (Benson et al., 1974).

Because the cardiovascular findings on back rubs are not conclusive enough to guide caregivers, and because of the need to address the central (heart rate, HR; stroke volume, SV; cardiac output, Q) and peripheral (arteriovenous oxygen difference, a-v[O.sub.2] diff) components of the change in oxygen consumption ([VO.sub.2]), the present study was therefore designed to compare [VO.sub.2] and the central and peripheral components that contribute to it at rest with and without the back rub. We also investigated the effects of the back rub on selected hemodynamic responses (systolic blood pressure, SBP; diastolic blood pressure, DBP; mean arterial pressure, MAP; and double product, DP) at rest. Our null hypothesis was that in healthy adults, without inherent or induced cardiovascular dysfunction, the responses during rest would not change with the back rub.

Methods

Subjects and Experimental Design

Twelve physically healthy college-age students (6 male and 6 female) volunteered to participate in this study. Their physical characteristics are mean age = 22.4 [ or -] 2 years, height = 177 [ or -] 7 cm, and body mass 78 [ or -] 10 kg. The experimental design was explained to all subjects, and informed consent was obtained. On Day One of the two-day protocol, the subjects went to the Exercise Physiology Laboratory where they were familiarized with the data collection procedures and experimental design. The monitors were turned on and calibration checks were completed. During Day Two, the subject and investigators went to the laboratory to collect data. The room temperature was measured and recorded during the calibration check.

Using an ABA design, the subject was assisted to a comfortable position on a padded plinth lying on one side so that the back was accessible for the back rub. The subject rested for 10 minutes (Control #1). The investigator then immediately administered a 1 O-minute back rub using warm unscented massage oil as the lubricant. The back rub (Treatment) consisted of basic Swedish massage strokes (Jensen-Nelson, 1948). At first, the subject's skin was stroked with the hands facing palms downward (effleurage). Then, during the last minute of the rub, the subject's skin was gently lifted with a C-shaped motion of the hand (petrissage). Following the treatment, the subject remained motionless for a 10-minute quiet period (Control #2).