C-33 Free Communication/Poster - Acute Exercise - Cardiorespiratory Physiology Thursday, May 31, 2018, 7:30 AM - 12:30 PM Room: CC-Hall B
Older individuals are at increased cardiovascular risk both during rest and during physical effort. Acute resistance exercise (RE) conducted at high intensity significantly increases heart rate (HR), blood pressure (BP), and arterial stiffness in young individuals. The effects of high (HI) and low intensity (LI) RE performed until failure on cardiovascular responses are likely different among populations of different ages.
PURPOSE: Compare the effects of acute HI and LI between young (Y) and older adults (O) on cardiovascular recovery responses.
METHODS: 9 Y and 9 O performed two experimental sessions in randomized sequence, using leg press, with 4 sets until failure for HI (80% 1RM) and for LI (30% 1RM). Pre, 3-min and 30-min post-RE beat-to-beat BP waveforms were recorded by finger photoplethysmography from which the hemodynamic variables (HR, stroke volume [SV], cardiac output [CO], total peripheral resistance [TPR]) were derived. Left common carotid artery images were acquired by ultrasound and carotid compliance (CC) were calculated. Two-way ANOVAs were performed on raw (mean BP, HR, CO) and normalized (SV, TPR, CC) data. Data is presented as mean ± standard deviation.
RESULTS: Following HI RE there was an increase in HR in Y (56 ± 8 to 95 ± 23) with no changes in O (64 ± 8 to 81 ± 12) at 3-min post-RE (interaction, p < 0.05), with similar increases in HR in Y and O following LI RE (Y: 56 ± 8 to 94 ± 12 and O: 66 ± 10 to 90 ± 13; time, p < 0.05). Y increased CO (6.1 ± 0.8 to 10.9 ± 3.2) and reduced TPR (0.81 ± 0.14 to 0.45 ±0.16) 3-min post HI RE while O did not change (CO 5.6 ± 0.9 to 7.6 ± 2.0 and TPR 1.02 ± 0.23 to 0.79 ± 0.24) (interaction, p < 0.05). No interactions were seen for the other variables.
CONCLUSION: Aging impacts the hemodynamic recovery following HI RE but aging does not impact hemodynamic recovery following LI RE. These data suggest that LI RE may be a more desirable form of RE for older individuals.