Endurance training in older men and women. I. Cardiovascular responses to exercise

TLDR

Eleven older adults (average age 63) were evaluated before training, after six months of low‑intensity endurance training, and after an additional six months of higher‑intensity training to assess changes in VO₂max and its determinants. Prolonged endurance training increased VO₂max by 30% in older adults, primarily via an enhanced maximal arteriovenous O₂ difference, with minimal changes in cardiac output, while improving stroke volume and reducing heart rate, blood pressure, and systemic vascular resistance at both absolute and relative workloads.

Abstract

The effects of prolonged endurance training on maximal O2 uptake capacity (VO2max) and its determinants were studied in 11 older individuals (63 +/- 2 yr). The subjects were evaluated before training, after 6 mo of low-intensity (LI) training, and after an additional 6 mo of higher intensity (HI) training. VO2max was 25.4 +/- 4.6 ml X kg-1 X min-1 before training, 28.2 +/- 5.2 ml X kg-1 X min-1 after LI training (P less than 0.05), and 32.9 +/- 7.6 ml X kg-1 X min-1 after HI training (P less than 0.01), with an overall increase of 30%. The increase in VO2max in response to training appeared to be mediated primarily through an increase in maximal arteriovenous O2 difference (P less than 0.01), with little augmentation of maximal cardiac output (Q) (P greater than 0.05). At the same absolute work rates, stroke volume was higher (P less than 0.05); heart rate (HR), blood pressure (BP), and systemic vascular resistance were lower (P less than 0.05); and Q and arteriovenous O2 difference were unchanged after training. At the same relative work rates, arteriovenous O2 difference was higher (P less than 0.01); BP and systemic vascular resistance were lower (P less than 0.05); and HR, Q, and stroke volume did not change significantly. These findings show that older individuals can adapt to prolonged endurance training with a large increase in aerobic power.