Muscle Strength Influences Pressor Responses to Static Handgrip in Men and Women.

Abstract

Whether differences in absolute muscle strength affect blood pressure (BP) responses to relative intensity static exercise remains controversial but could contribute to known sex-based differences and influence the interpretation of cross-sectional data. One hundred thirty-two healthy participants (66 men and 66 women; age, 22 ± 3 yr) underwent continuous seated measurements of BP (Finometer) and heart rate (electrocardiography) during baseline rest and 2 min of static handgrip (30% maximal voluntary contraction (MVC)). BP and heart rate responses were quantified in 30-s epochs during exercise and compared between men and women with and without statistical adjustment (ANCOVA) for differences in baseline BP (or heart rate), forearm girth, and handgrip MVC. Within each sex, BP and heart rate responses were compared also between tertiles of handgrip MVC (n = 22 per group). Men had larger systolic, diastolic, and mean arterial pressure responses during static handgrip than did women (interaction term, all P < 0.0005), although heart rates responses were similar (interaction term, P = 0.25). These sex-based BP differences persisted after statistical adjustment for differences in baseline BP or forearm girth; however, controlling for handgrip MVC abolished differences in BP responses during static handgrip exercise between men and women (interaction term, all P > 0.35). In men, BP responses were smaller within the lowest tertile of handgrip MVC (interaction term, all P < 0.006), whereas in women, BP responses were larger within the highest tertile of handgrip MVC (interaction term, all P < 0.04). Our findings suggest an important between- and within-sex role of absolute handgrip strength in mediating the BP response to static handgrip exercise and highlight the importance of controlling for interindividual differences in future work.