The effect of age on mechanisms of exercise tolerance: Reduced arteriovenous oxygen difference causes lower oxygen consumption in older people

Amy Fuller, Nduka Okwose, Jadine Scragg, Christopher Eggett, Peter Luke, Alykhan Bandali, Radmila Velicki, Laura Greaves, Guy MacGowan, Djordje G Jakovljevic

    Research output: Contribution to journalArticlepeer-review

    1 Citation (Scopus)
    6 Downloads (Pure)

    Abstract

    OBJECTIVE: To assess the effect of age on mechanisms of exercise tolerance.

    METHODS: Prospective observational study recruited 71 healthy individuals divided into two groups according to their age i.e. younger (≤40 years of age, N = 43); and older (≥55 years of age, N = 28). All participants underwent maximal graded cardiopulmonary exercise stress testing using cycle ergometer with simultaneous non-invasive gas-exchange and central haemodynamic measurements. Using the Fick equation, arteriovenous O2 difference was calculated as the ratio between measured O2 consumption and cardiac output.

    RESULTS: The mean age of younger and older participants was 26.0 ± 5.7 years, and 65.1 ± 6.6 years respectively. Peak O2 consumption was significantly lower in older compared to the younger age group (18.8 ± 5.2 vs 34.4 ± 9.8 ml/kg/min, p < 0.01). Peak exercise cardiac output and cardiac index were not significantly different between the younger and older age groups (22.7 ± 5.0 vs 22.1 ± 3.9 L/min, p = 0.59; and 12.4 ± 2.9 vs 11.8 ± 1.9 L/min/m2, p = 0.29). Despite demonstrating significantly lower peak heart rate by 33 beats/min (129 ± 18.3 vs 162 ± 19.9, p < 0.01), older participants demonstrated significantly higher stroke volume and stroke volume index compared to the younger age group (173 ± 41.5 vs 142 ± 34.9 mL/min, p < 0.01; and 92.1 ± 18.1 vs 78.3 ± 19.5 mL/m2, p < 0.01). Arteriovenous O2 difference was significantly lower in older compared to younger age group participants (9.01 ± 3.0 vs 15.8 ± 4.3 mlO2/100 mL blood, p < 0.01).

    CONCLUSION: Ability of skeletal muscles to extract delivered oxygen represented by reduced arteriovenous O2 difference at peak exercise appears to be the key determinant of exercise tolerance in healthy older individuals.

    Original languageEnglish
    Article number111340
    JournalExperimental Gerontology
    Volume149
    Early online date8 Apr 2021
    DOIs
    Publication statusPublished - 1 Jul 2021

    Bibliographical note

    © 2021, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/

    Copyright © and Moral Rights are retained by the author(s) and/ or other copyright owners. A copy can be downloaded for personal non-commercial research or study, without prior permission or charge. This item cannot be reproduced or quoted extensively from without first obtaining permission in writing from the copyright holder(s). The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the copyright holders.

    Keywords

    • Ageing
    • Arteriovenous oxygen difference
    • Exercise testing
    • Exercise tolerance
    • Risk factors

    ASJC Scopus subject areas

    • Biochemistry
    • Ageing
    • Molecular Biology
    • Genetics
    • Endocrinology
    • Cell Biology

    Fingerprint

    Dive into the research topics of 'The effect of age on mechanisms of exercise tolerance: Reduced arteriovenous oxygen difference causes lower oxygen consumption in older people'. Together they form a unique fingerprint.

    Cite this