Proceedings of The Physiological Society

Europhysiology 2018 (London, UK) (2018) Proc Physiol Soc 41, C050

Oral Communications

Two-weeks of time-efficient high-intensity interval training (HIIT) does not appear sufficient to elicit cardiorespiratory fitness gains in older adults

P. J. Herrod1,2, A. L. Torkington1, J. E. Blackwell1,2, D. Battacharjee1,2, T. S. Sian1,2, J. P. Williams1,2, J. N. Lund1,2, B. E. Phillips1

1. MRC-ARUK Centre for Musculoskeletal Ageing Research, University of Nottingham, Derby, United Kingdom. 2. Division of Surgery and Anaesthetics, Royal Derby Hospital, Derby, United Kingdom.

BACKGROUND: Declines in cardiorespiratory fitness (CRF) and physical function with advancing age are both associated with increased morbidity and mortality per se (1), as well as in the peri-operative period (2). Given the increasing number of older adults presenting for surgery (3), and the time-constrains often imposed on the preoperative period, time-efficient high-intensity interval training (HIIT) may be a promising surgical ‘prehabilitation' tool (4). However, whether a HIIT protocol that has been shown to induce meaningful increases in CRF in older adults in 4-weeks, can elicit improvements in CRF and physical function in just 2-weeks; a common time-to-treatment window for a number of major intra-abdominal surgeries, is not yet known. METHODS: Seven (3 male: 4 female) independent community-dwelling volunteers aged 73 (70-78) years, with no co-morbidities that excluded them from exercise testing in accordance with the American Thoracic Society (ATS) Cardiopulmonary Exercise Test (CPET) Guidelines (5), undertook six sessions of time-efficient reduced-intensity HIIT over 2-weeks. Each session lasted 16.5 minutes, including five 1-minute efforts at 100-110% watt max. CPET was used before and after the HIIT intervention to assess CRF and exercise performance, with timed up-and-go (TUG) used to assess global physical function. RESULTS: Neither anaerobic threshold ((AT);12.11±1.83 vs. 12.73±2.84 ml/kg/min, p=0.62) or VO2peak (21.5±4.2 vs. 22.8±4.0 ml/kg/min, p=0.26) significantly increased following our HIIT intervention, despite over half of our volunteers achieving the previously reported threshold for a clinically meaningful improvement in AT (>1.5 ml/kg/min). There was no relationship between baseline CRF and magnitude of change for either AT(r2=0.2, p=0.32) or VO2peak (r2=0.15, p=0.40). Despite the lack of significant improvement in CRF parameters, exercise performance (856±130 vs. 973±132 seconds, p=0.03) and global physical function increased significantly after HIIT (TUG: 7.38±1.53 vs. 6.13±1.65 seconds, p=0.005). No adverse events were encountered during the HIIT, with volunteers reporting high levels of acceptability and enjoyment. CONCLUSION: Despite our well-tolerated, time-efficient HIIT programme being able to improve the CRF of older adults in a 4-week period, 2-weeks does not appear to be a long enough duration to elicit comparable gains. Despite these findings, 2-weeks of our HIIT programme can improve aspects of physical function in older adults, and as such has the potential to improve postoperative outcomes. In addition, further research in a larger cohort is required to determine the true utility of this intervention for improving CRF in older adults.

Where applicable, experiments conform with Society ethical requirements