Impact Of Systemic Hypertension On The Cardiovascular Response To Exercise

In the United States, nearly 50% of adults have systemic hypertension (HTN). During submaximal exercise, the blood pressure response is exaggerated in HTN compared to normotensive adults. Importantly, the exaggerated blood pressure response during exercise in HTN adults is associated with a significantly higher risk of cardiovascular events. During smaller muscle mass exercise, adults with HTN have exaggerated increases in systemic vascular resistance (SVR) compared to normotensive adults. It is unclear if the augmented blood pressure during whole-body submaximal exercise in HTN adults is due to higher SVR or cardiac output. PURPOSE: We hypothesized that adults with HTN would have higher blood pressure during submaximal exercise due to higher SVR compared to age matched normotensive controls (CTL). METHODS: Normotensive (n = 8; age: 54 ± 14 years; BMI: 28 ± 3 kg/m2) and hypertensive (n = 12; age: 52 ± 12 years; BMI: 28 ± 3 kg/m2) adult participants performed an incremental cycling test until task failure. Measurements included manual sphygmomanometry for blood pressure, open-circuit acetylene wash-in technique for cardiac output, and SVR was calculated. Data is reported at baseline and during submaximal cycling exercise at 60 W. RESULTS: At baseline, the HTN group had higher MAP (HTN: 99 ± 6 vs. CTL: 91 ± 8 mmHg) than controls (p = 0.03), while systolic blood pressure, cardiac output (HTN: 5.4 ± 0.7 vs. CTL: 5.3 ± 0.8 L/min) and SVR (HTN: 18.6 ± 3.1 vs. CTL: 17.4 ± 2.6 mmHg/L/min) were not different between groups (all, p > 0.29). During 60 W cycling exercise, the HTN group had higher MAP (HTN: 107 ± 7 vs. CTL: 96 ± 5 mmHg) and systolic blood pressure compared to controls (both, p < 0.01). During 60 W cycling exercise, the HTN group had higher SVR (HTN: 10.2 ± 1.3 vs. CTL: 9.0 ± 0.5 mmHg/L/min) compared to controls (p = 0.03). In contrast, no differences were present in cardiac output (HTN: 10.6 ± 1.6 vs. CTL: 10.8 ± 1.1 L/min), heart rate, or stroke volume between groups (p > 0.31). CONCLUSIONS: These findings support our hypothesis that the higher MAP during submaximal exercise in patients with HTN is due, in part, to heightened SVR. Supported by: American Heart Association Career Development Award (935610)