Insufficient 25-hydroxyvitamin D [25(OH)D] levels are associated with high resting blood pressure (BP). However, the relationship between 25(OH)D and the peak systolic BP (SBP) response to exercise, a predictor of future hypertension, has yet to be investigated. We sought to examine the relationship among serum 25(OH)D and the peak SBP response to a graded exercise stress test (GEST) among a large sample (n = 417) of healthy men (49%) and women (51%) over a broad age range (20-76 years; mean age: 44.1 ± 0.8 years). We hypothesized that individuals with clinically insufficient 25(OH)D would have a greater peak SBP response to a GEST compared to individuals with sufficient 25(OH)D levels. Fasting serum 25(OH)D, anthropometrics, resting BP, and peak exercise SBP were obtained at the baseline visit of a larger clinical trial (STOMP; NCT01140308). Mean 25(OH)D levels were 36.1 ± 0.7 ng/ml, with ∼35% of individuals classified as insufficient (<30 ng/ml). Average resting BP was 119 ± 13 mmHg/75 ± 10 mmHg, with 52.3% considered to have normal BP, while 25.2% had elevated BP and 22.5% had established hypertension. The peak SBP response to a GEST was similar between individuals with sufficient (48 ± 19 mmHg) versus insufficient (48 ± 18 mmHg) 25(OH)D (p = 1.000). One unexpected finding emerged such that individuals with sufficient 25(OH)D had higher resting SBP (120 ± 14 mmHg vs. 117 ± 13 mmHg; p = .020) than individuals with insufficient 25(OH)D. In contrast to our hypothesis, 25(OH)D levels were not associated with the peak SBP response to a GEST. Baseline 25(OH)D levels were positively correlated with resting SBP; however, the magnitude of this effect is likely not clinically meaningful.
Keywords: biomarker; cholecalciferol; hypertension; vitamin D deficiency.