Effects Of Habitual Isometric Handgrip Exercise On Central Blood Pressure In Older Adults

Abstract

Central (aortic) blood pressure (BP) is a more important predictor of cardiovascular diseases than peripheral (brachial) BP. Isometric handgrip exercise can effectively decrease peripheral BP. However, effects of isometric handgrip exercise on central BP remain unknown. PURPOSE: The present study aimed to determine whether habitual isometric handgrip exercise decreases central BP in older adults with stage 1 and 2 hypertension. METHODS: Twenty-four males and females (mean age 63±2 y; ± SEM) with stage 1 and 2 hypertension (brachial systolic or diastolic BP of 140-179 or 90-109 mmHg, respectively) who were not actively involved in regular resistance or endurance training were randomly assigned to a group that did isometric handgrip exercise (IHG) or a control (CON) group. The isometric handgrip exercise comprised four unilateral 2-min isometric contractions at 30% of maximal voluntary contraction using a programmed handgrip dynamometer with 1-min rest periods for five days per week for four weeks. Central systolic BP (cSBP), brachial systolic BP (bSBP), brachial diastolic BP (bDBP), and the augmentation index at a heart rate of 75 beats per minute (AIx75) were non- invasively measured after resting in the supine position for at least five minutes in both groups before (baseline) and after four weeks of training using an automated applanation tonometric system. RESULTS: Baseline cSBP, bSBP, bDBP, and AIx75 did not significantly differ between the groups. Consistent with previous studies, bSBP and bDBP after training significantly decreased from baseline from 155±3 to 142±3 mmHg and from 94±3 to 88±2 mmHg, respectively (p<0.05 for both). The cSBP and AIx75 did not change in the CON group, but significantly decreased from baseline after training in the IHG group from 165±4 to 148±4 mmHg and from 88±4% to 82±4%, respectively (p<0.05 for both). The cSBP was significantly lower after training in the IHG than in the CON group (148±4 vs. 159±3 mmHg, p<0.05). CONCLUSIONS: These results suggest that isometric handgrip exercise could reduce central BP in older adults with stage 1 and 2 hypertension. Therefore, isometric handgrip exercise might be an effective non- pharmacological therapy for prevention and treatment of cardiovascular disease.