Meeting international aerobic physical activity guidelines is associated with enhanced cardiovagal baroreflex sensitivity in healthy older adults
Cardiovagal baroreflex sensitivity (cvBRS) reflects the efficiency of modulating heart rate in response to changes in systolic blood pressure. International guidelines recommend that older adults achieve at least 150 min of moderate–vigorous physical activity per week. We tested the hypothesis that older adults who achieve these guidelines will exhibit greater cardiovagal baroreflex sensitivity versus those who do not.
A cross-sectional comparison of older adults who did (active, 66 ± 5 years, 251 ± 79 min/week; n = 19) and who did not (inactive, 68 ± 7 years, 89 ± 32 min/week; n = 17) meet the activity guidelines. Beat-by-beat R–R intervals (electrocardiography) and systolic blood pressure (finger photoplethysmography) were recorded. Spontaneous cardiovagal baroreflex sensitivity was assessed using the sequence technique from 10 min of resting supine data. Cardiovagal baroreflex function was also measured during early phase II and phase IV of the Valsalva maneuver. Peak oxygen uptake was determined during maximal cycle ergometry. Moderate–vigorous intensity physical activity and time spent sedentary were assessed over 5 days using the PiezoRx and activPAL, respectively.
Groups had similar peak oxygen uptake (active 25 ± 9 vs. inactive 22 ± 6 ml/kg/min; p = 0.218) and sedentary time (active 529 ± 60 vs. inactive 568 ± 88 min/day; p = 0.130). However, the active group had greater (all, p < 0.019) cvBRS at rest (9.1 ± 2.7 vs. 5.0 ± 1.9 ms/mmHg), during phase II (8.2 ± 3.8 vs. 5.4 ± 2.1 ms/mmHg), and during phase IV (9.9 ± 3.8 vs. 5.6 ± 1.6 ms/mmHg). In the pooled sample, moderate–vigorous physical activity was positively correlated (all, p < 0.015) with spontaneous (R = 0.427), phase II (R = 0.447), and phase IV cvBRS (R = 0.629).
Independent of aerobic fitness and sedentary time, meeting activity guidelines was associated with superior cardiovagal baroreflex sensitivity at rest and during the Valsalva maneuver in older adults.
KeywordsAgeing Blood pressure regulation Valsalva maneuver Objectively measured physical activity
Support provided by: Canadian Foundation for Innovation: Leader’s Opportunity Fund (DSK) (28311), Faculty of Health Professions Research Development (DSK), Nova Scotia Health Research Foundation (NSHRF) (2016-3993) Development/Innovation (DSK and SM) Grants, as well as the Acadia University McCain Foundation Fund (SM). MWO was supported by a Heart & Stroke BrightRed Scholarship, NS Graduate Scholarship and an NSHRF Scotia Scholars Award.
Compliance with ethical standards
Research ethics board approval was attained from both Dalhousie and Acadia University. Participants provided written, informed consent prior to study enrollment.
JRF received unrestricted funding from Steps Count Inc. and is the National Chair of Exercise is Medicine Canada.
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