Abstract
OBJECTIVE: This study examined the contributions of fat mass (FM) and fat-free mass (FFM) to the magnitude of exercise pressor responses in humans. METHODS: The cumulative blood pressure responses (blood pressure index; BPI) to handgrip exercise (BPI(hg)), post-exercise-circulatory-occlusion (BPI(peco)), and cold-pressor activation (BPI(cpt)) were collected from 67 individuals grouped by BMI (27.8 ± 7.3 kg/m(2)), FFM index (FFMi, 29.1 ± 3.8 kg/m(2)), and FM index (FMi 12.5 ± 4.8 kg/m(2)) quartiles. BPI responses to HG were also normalized to the time-tension index of HG, providing a relative index of exercise pressor response magnitude (BPI(norm)). RESULTS: BPI(hg) and BPI(peco) were significantly elevated in the third FFMi quartile (p ≤ 0.034), while BPI(norm) significantly decreased in the second and fourth quartiles (p ≤ 0.029). In contrast, no differences in BPI(cpt) were observed across any FFMi, BMI, or FMi quartiles (p ≥ 0.268). FFM was independently associated with BPI(hg,) BPI-(peco), and BPI(norm) (all p ≤ 0.049), however, FFM was eliminated as an independent predictor when maximal voluntary contraction (MVC) was included in these regression models (all p ≥ 0.495). Neither FFM nor MVC was associated with BPI(cpt) (p ≥ 0.229). CONCLUSIONS: These findings indicate that exercise pressor responses, but not cold-pressor responses, are significantly associated with FFM in humans, and that this association is driven by FFM related differences in MVC.