dc.contributor.author | Ramsay, Diane | |
dc.date.accessioned | 2016-08-04T15:24:27Z | |
dc.date.available | 2016-08-04T15:24:27Z | |
dc.date.issued | 2016-08-04T15:24:27Z | |
dc.identifier.uri | http://hdl.handle.net/10222/72034 | |
dc.description.abstract | Optimal blood vessel function requires a balance between sympathetic neural vasoconstrictor activity (SNA) and endothelial-derived vasodilatory nitric oxide (NO) bioavailability. Ageing is associated with elevated resting SNA and reduced NO production. Aerobically-trained older adults (OT) have higher SNA compared with their untrained age-matched peers (OU). An explanation for higher SNA is unclear but may serve to ‘buffer’ a corresponding increase in NO production.
PURPOSE. To test the hypothesis that OT will: 1) have higher resting SNA than aerobic fitness-matched young adults (YA) and OU, 2) have similar endothelial-mediated NO production to YA, but greater than OU, and 3) observe a positive relationship between resting SNA and popliteal artery (PA) flow-mediated dilation (FMD).
METHODS. Resting common fibular nerve muscle SNA (MSNA, microneurography) and PA endothelial-dependent FMD were determined in 8 YA (23±2yrs, VO2peak 49.2±9.4mLO2/kg/min), 8 OU (63±6yrs, VO2peak 28.1±5.2mLO2/kg/min), and 8 OT (65±3years, VO2peak 49.4±3.2mL O2/kg/min).
RESULTS. MSNA was higher in OT than YA (71±20 vs. 29±19 bursts/100heartbeats; p=0.006) but not OU (43±32 bursts/100heartbeats; p=0.1). FMD was higher in both YA and OT (9.5±1.5% and 12.1±2.4%, respectively) than OU (6.7±1.1%, all, p<0.02). In OT, the correlation between MSNA and FMD was significant (r=0.89, p=0.003).
CONCLUSIONS. This study marks the first attempt to concurrently measure MSNA and FMD in older adults. Our data suggests that exaggerated resting MSNA levels in OT adults may be a compensatory mechanism to ‘buffer’ a corresponding increase in NO production to maintain vascular tone and arterial pressure. | en_US |
dc.language.iso | en | en_US |
dc.subject | endothelial function | en_US |
dc.subject | ageing | en_US |
dc.subject | muscle sympathetic nerve activity | en_US |
dc.subject | aerobic fitness | en_US |
dc.subject | Aerobic exercises | |
dc.title | Blood Vessel Health: The Influence of Ageing and Aerobic Fitness | en_US |
dc.date.defence | 2016-06-27 | |
dc.contributor.department | School of Health & Human Performance | en_US |
dc.contributor.degree | Master of Science | en_US |
dc.contributor.external-examiner | Dr. Philip Millar | en_US |
dc.contributor.graduate-coordinator | Dr. Lynne Robinson | en_US |
dc.contributor.thesis-reader | Dr. Scott Grandy | en_US |
dc.contributor.thesis-reader | Dr. Gail Dechman | en_US |
dc.contributor.thesis-supervisor | Dr. Derek S. Kimmerly | en_US |
dc.contributor.ethics-approval | Received | en_US |
dc.contributor.manuscripts | Not Applicable | en_US |
dc.contributor.copyright-release | Not Applicable | en_US |