Physical activity was significantly associated with seasonal variation in specific heart rate variability indices, though regional heterogeneity was primarily reflected in unexplained components.
Observational (n=133,747)
Yes
Seasonal variation in heart rate variability is associated with physical activity in an index-specific manner, with significant regional heterogeneity primarily reflected in unexplained components beyond behavioral influences.
Seasonal variation in heart rate variability (HRV) reflects multiple interacting determinants rather than a single underlying determinant. In this study, we aimed to examine subgroup-level seasonal HRV variation in relation to physical activity (PA) using large-scale real-world data. We analyzed 133,747 24-h ECG recordings with tri-axial accelerometry from the ALLSTAR database across eight regions in Japan (after excluding regions with insufficient sample sizes) collected between 2015 and 2021. Seasonal variation (Δ) was defined as the difference between the maximum and minimum seasonal mean values. Weighted least squares models (WLS) were applied to examine associations between ΔPA and multiple HRV indices, including interaction terms for sex and region, while regional differences in residual variability were assessed using Levene’s test. During the normal period, significant associations between ΔPA and ΔHRV were observed for specific indices (ΔULF, ΔVLF, ΔHF, and ΔLF/HF), whereas other indices were not significant. During the Coronavirus Disease 2019 (COVID-19) period, significant associations were observed for ΔRRI, ΔSDRR, and ΔLF/HF, indicating that the association between PA and seasonal HRV variation was index-specific. Sex interactions were not statistically significant after FDR (False Discovery Rate) correction in either period, suggesting a limited role of sex in the PA–HRV relationship at the population level. Regional differences in HRV sensitivity to PA were statistically significant but heterogeneous across regions. In contrast, residual variability exhibited significant regional differences across multiple HRV indices in both periods. These patterns were not fully explained by sample size and showed stable regional heterogeneity. These findings suggest that subgroup-level regional heterogeneity in seasonal HRV variation is primarily reflected in the unexplained component rather than in the direct PA–HRV relationship, indicating the presence of region-specific variability in the unexplained component beyond behavioral influences.
Yoshida et al. (Mon,) reported a observational. Physical activity was evaluated on Association between seasonal variation in physical activity (ΔPA) and multiple HRV indices. Physical activity was significantly associated with seasonal variation in specific heart rate variability indices, though regional heterogeneity was primarily reflected in unexplained components.