Testing an association between baseline resting pulse rate averages and short-term changes in resting pulse rates: A pilot study.

INTRODUCTION: Resting heart (pulse) rate (RPR) monitoring may be a useful neurological assessment tool in chiropractic practice. Lower RPR generally reflects a better level of fitness and health status than higher RPR. However, the clinical significance of short-term changes in RPR remains unknown. The purpose of this study was to take an initial step towards understanding the clinical significance of short-term RPR changes, first, by describing short-term RPR changes between duplicated measurements, and second, by comparing RPR changes between groups with lower and higher baseline RPR.

METHODS: Seventy-three healthy adult volunteers received an RPR measurement on two days within a 1-week period. The mean difference between the two measurements (RPR change) in patients with lower versus higher baseline RPR was compared.

RESULTS: Mean RPR change in the low baseline group was -0.3 BPM (95% confidence interval [CI] = -2.7 to 2.1 BPM) whereas in the high baseline group, it was +4.4 BPM (95% CI = 1.2 to 7.6). This difference between groups was statistically significant (P = 0.02) Testing an association between baseline resting pulse rate averages and short-term changes in resting pulse rates: A pilot study with a large effect size (Cohen's d = 0.57).

CONCLUSION: In this pilot study, a higher RPR at baseline was associated with increased RPR change, whereas a lower baseline RPR was associated with a stable or reduced RPR change. A future main study with a larger sample size and longer follow-up period is needed to better characterize both the natural variation of RPR over multiple repeated measurements, and the clinical significance of short-term RPR changes in terms of predicting longer-term health outcomes.