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Individual Differences in Components of the Pressor Responses to Isometric and Dynamic Handgrip Exercise in Humans
Author(s) -
Watanabe Kazuhito,
Ichinose Masashi,
Tsuji Bun,
Maeda Seiji,
Nishiyasu Takeshi
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.1289.2
Subject(s) - isometric exercise , supine position , cold pressor test , analysis of variance , cardiology , medicine , blood pressure , physical therapy , physical medicine and rehabilitation , heart rate
The aim of this study was to test the hypotheses that, in humans, cardiac output (CO) and total peripheral vascular resistance (TPR) responses to dynamic handgrip exercise vary among individuals as demonstrated recently with isometric handgrip exercise, and that the responses of the components mediating the pressor response have a similarity between those exercises in the same individuals. We studied 30 healthy male and female volunteers with a mean age of 25 ± 0.5 yr, body weight of 64 ± 2.4 kg, and height of 169 ± 1.5 cm (means ± SE). The subjects assumed a supine position and performed isometric and dynamic (30 contractions/min) handgrip exercise at 50% of maximal voluntary contraction until fatigue separately (84 ± 3 s and 178 ± 14 s, respectively). We assessed the magnitude of the variance in the individual changes in mean arterial pressure (MAP), CO and TPR at 20%, 40%, 60%, 80% and 100% of fatigue using inter individual coefficient of variation (CV). Although CVs for changes in CO and TPR between the rest and the exercise periods were not much different from the CV for change in MAP at 20% of fatigue, the CVs for changes in CO and TPR were 2‐ to 3‐fold greater than the CV for change in MAP at ≥40% of fatigue in both trials. Thus the components of the pressor responses to isometric as well as dynamic handgrip exercise varied widely among subjects at ≥40% of fatigue. In addition, the CO and TPR responses during dynamic handgrip exercise correlated positively with the corresponding responses during isometric handgrip exercise from 20% to 100% of fatigue (CO: r = 0.675–0.755, P < 0.01; TPR: r = 0.566–0.788, P < 0.01). Our findings demonstrate that the CO and TPR responses during moderate to exhaustive handgrip exercise (≥40% of fatigue) vary considerably among individuals compared to the pressor response irrespective of the exercise modality (isometric or dynamic). They also suggest that the CO and TPR responses to handgrip exercise is similar between the modalities in the same individuals throughout the course of exercise. Support or Funding Information This study was supported by the grants from Japan Society for the Promotion of Science.