Physical activity is not associated with resting heart rate variability in young adults

Abstract

Background: Higher total minutes of weekly physical activity (PA) have been associated with higher heart rate variability (HRV) in young adults. Research is yet to investigate this relationship using objective measures with greater control over influencing variables. Technology provides a more practical approach to monitoring HRV remotely, but many methods are yet to be validated. Objectives: The purpose of this study was to investigate the relationship between total minutes of PA per week and resting 5-minute HRV in healthy adults. The agreement between HRV parameters measured by a smartphone app and ECG monitor were measured 5-minute resting measurement. Methods: An observational, cross-sectional study was used. Twenty-eight participants wore an ActiheartTM monitor for seven-days. Participants then reattended the laboratory to complete a stress questionnaire, prior to a simultaneous 5-minute resting HRV measurement taken on an ECG monitor and the Welltory app. Multivariate regression analyses were used to determine whether total minutes of light, moderate, vigorous and very vigorous PA could predict HRV parameters (RMSSD, SDNN). The agreement between the Welltory app and an ECG for each HRV parameter were compared using a Bland-Altman plot. Results: Total minutes of all PA intensities over the seven-days were unable to significantly predict lnSDNN (p = .558) and lnrMSSD (p = .516), in unadjusted and adjusted models. The Welltory app tended to overestimate lnSDNN and lnrMSSD in comparison to ECG and did not demonstrate strong validation correlation coefficients for either HRV parameter (r = 0.71 and 0.73, respectively). Conclusions: Further research is required in larger samples to solve the heterogeneity in the literature and explore the mediation between PA and HRV. Use of technology without adequate validation should be discouraged to avoid misinforming users.

Date of Award	2020
Original language	English
Awarding Institution	University of Bath
Supervisor	Oliver Peacock (Supervisor)