Gender differences in cardiovascular response to upper limb isometric exercises
Background: Isometric exercise remains an important modality in patientís rehabilitation and also employed in advanced strength and endurance training programs. Numerous studies attempting to explain gender differences in cardiovascular response to isometric exercise are inconsistent at best and conflicting. The purpose of this study was to determine if the cardiovascular responses to upper limb isometric exercises differ between healthy normotensive male and female students. Methods: 30 normotensive males and females in the age group of 18-30 years were randomly selected. Their anthropometric variables namely height, weight and body mass index were recorded. Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), Heart Rate (HR) and Rate Pressure Product (RPP) before and after three upper limb isometric exercises were used to assess the cardiovascular response. Studentís paired t-test was used to compare intra group pre and post exercise cardiovascular parameters. Unpaired t-test was used to compare physical characteristics and pre and post exercise cardiovascular parameters between genders. Level of significance was set at p<0.05. Results: Post exercise cardiovascular parameters were significantly greater (p<0.05) than baseline values without gender bias. However the post exercise HR, SBP, DBP and RPP were significantly greater in males than females. Highly significant increase in post exercise HR, SBP, DBP and RPP was observed in males compared to females indicating that men undergo significant changes in either cardiac output, total peripheral resistance, or increase in level of circulating catecholamines mainly epinephrine with many possible explanations. Also there was significant increase in myocardial oxygen uptake which is indicated by RPP.
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