Objective: Heart rate recovery index (HRRI) and mean platelet volume (MPV) are two cardiovascular prognostic markers. Low HRRI and high MPV values have been observed in several diseases and conditions. However, the relationship between these two markers is unclear. In this study, the relationship between HRRI and MPV in healthy individuals is examined.
Materials and Methods: The exercise tests performed between January and December 2020 were evaluated, and 120 individuals who met the study criteria were included in the present study. An abnormal HRRI was defined as a decrease in heart rate of 12 beats or more until one minute after the peak of exercise. Those with abnormal HRRI were defined as the study group (n=60), and those with normal HRRI as the control group (n=60).
Results: A total of 120 healthy individuals were included in the study (54% female; mean age 40.14±7.90 years). Higher MPV values were detected in the study group when compared to the control group (10.27±0.10 fl vs. 9.44±0.12 fl; p<0.001). This significance continued in the logistic regression analysis (odds ratio=3.78, p<0.001). In addition, a moderate negative correlation was found between HRRI and MPV (r=-0.404, p<0.001). The MPV value of 10.25 fl was identified as an effective cutoff point for the prediction of abnormal HRRI (area under the curve [AUC]: 0.758; 95% confidence interval [CI]: 0.674–0.843).
Conclusion: Healthy individuals with abnormal HRRI have elevated MPV levels. Additionally, a negative correlation between MPV and HRRI in healthy subjects indicates a causal relation between MPV and autonomic dysfunction.