Seasonal variation in blood pressure control in healthy young adults

Cardiovascular disease is the leading cause of death worldwide, and cardiovascular death rates are highest during the winter months. Likewise, blood pressure (BP; a primary cardiovascular risk factor) is highest in the winter. However, there has yet to be a study of seasonal variations in baroreflex control of BP and/or BP responses to sympathoexcitatory stimuli. This study tested the hypotheses that resting BP and BP responses to the cold-pressor test (CPT) would be increased, and that spontaneous baroreflex sensitivity (BRS) would be decreased, in the winter/early-spring months compared with the summer/early-fall. We tested 13 healthy young adults (23 ± 2 yrs; 5 men, 8 women) during the summer/early-fall (June – October) and winter/early-spring (January – April). BP was measured with participants in a semi-supine position and is reported as the average of three separate measurements during quiet rest. Continuous blood pressure and heart rate were measured (finger photoplethysmography) at rest and during the CPT (0-3ºC water). BRS was determined using BP and R-R interval (in milliseconds; ms) data extracted from a 3-min period at baseline. Briefly, BRS was calculated as the average change in R-R interval per mmHg change in systolic BP across all sequences in which successive pressure pulses differed by at least 1.0 mmHg and R-R intervals differed by at least 5.0 ms. SBP (115 ± 12 mmHg vs. 110 ± 8 mmHg; P = 0.12), DBP (72 ± 9 mmHg vs. 68 ± 6 mmHg; P = 0.09), and MAP (84 ± 9 mmHg vs. 81 ± 8 mmHg, P = 0.23) were marginally, but not significantly, higher in the winter/early-spring months compared with summer/early-fall. There was no effect of season for any phase of the CPT (P ≥ 0.15). In contrast, BRS was higher in the summer/early-fall (25.7 ± 11.2 ms/mmHg) compared with winter/early-spring (18.8 ± 6.7 ms/mmHg; p=0.05). These findings suggest that baroreflex control of BP may be altered by season, potentially contributing to higher BP and increased cardiovascular risk in the winter compared with other seasons. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.