A Prospective Look at the Impact of Aging On Central Hemodynamics During Exercise in Men

Increases in elastic conduit artery stiffness with aging are associated with early wave reflection and consequently increases in left ventricular afterload, myocardial oxygen demand, and wasted left ventricular energy (LVEW). The effects of aging and increased arterial stiffness on central hemodynamics have not yet been characterized during incremental exercise. PURPOSE: This study sought to investigate the changes in central hemodynamics during a range of light to moderate intensity exercise in young, middle aged, and elderly men. METHODS: Central blood pressure and wave reflection characteristics were measured non-invasively using radial artery applanation tonometry at rest and during cycling exercise (45, 55 and 65% of age predicted maximal heart rate) in 14 young (Y: 24 ± 1 years), 16 middle age (M: 49 ± 2 years) and 13 elderly (E: 73 ± 2 years) men. RESULTS: Comparison of the Y, M, and E groups at rest revealed that age was associated with increases in central systolic blood pressures (Y: 106 ± 3, M: 116 ± 2, and E: 119 ± 3 mmHg), central pulse pressure (Y: 30 ± 2, M: 33 ± 1, and E: 39 ± 2 mmHg), AIx (Y: 13 ± 3%, M: 25 ± 3%, and E: 21 ± 3%) and LVEW (Y: 352 ± 212, M: 795 ± 205, and E: 1538 ± 240 dynes·s/cm2·min). Analysis of within-group responses to exercise revealed that peripheral diastolic pressure values decreased significantly relative to baseline in the oldest group (-4 ± 2 mmHg), did not change in the middle-aged (+1 ± 1 mmHg), and increased significantly relative to baseline in the young (+3 ± 1 mmHg). In addition, the elderly group had a significant increase in augmented pressure (+4 ± 1 mmHg) and LVEW (+760 ± 369 dynes·s/cm2·min) in response to exercise in marked contrast to the young and middle-aged groups which saw a significant decline in both augmented pressure (Y: -6 ± 1 and M: -3 ± 1 mmHg) and WLVE (Y: -494 ± 108 and M: -316 ± 136 dynes·s/cm2·min). CONCLUSIONS: The findings of this study suggest that aging is associated with stiffening of the elastic conduit arteries as evidenced by greater central pulse pressures and a decline in diastolic blood pressure with exercise. Consequently, early wave reflection increases augmented pressure and LVEW during cycling exercise in the elderly.