Principal Investigator: Dr John Williams

Lead institution: University of Nottingham

Award amount: £99,636

Prehabilitation HIIT: improving fitness for major surgery within 31 days from decision to treat

Access to major surgery declines substantially for people aged 75 and over; some operations are offered up to 35% less often to people aged 75, than to those aged 65. One reason for this is that, typically, aerobic fitness reduces as people age, increasing the risk of complications and death following surgery.

Exercise training programmes are shown to improve aerobic fitness, as measured by increased anaerobic threshold, leading to reduced surgical risk. However, such training programmes are rarely used in the lead-up to operations due to the time constraints involved — major surgery often needs to be performed within 31 days of diagnosis to meet NHS targets.

Despite this, a form of exercise training known as high intensity interval training (HIIT) — consisting of alternating periods of high-intensity exercise and recovery — has previously been shown to increase anaerobic threshold by 10-15% in healthy older people, after just 4 weeks of training. HIIT may therefore have the potential to increase aerobic fitness, and decrease surgical risk, in older patients within the limited timeframe between diagnosis and operation.

Project Aims

This project primarily aimed to assess the feasibility of delivering a 4-week HIIT programme for people aged 75 and over with co-morbid medical conditions. If feasible, and if improvements in participants’ physical performance were observed, then HIIT could provide a means to improve the health of older individuals prior to surgery. As a result, older patients could then access treatment that is otherwise often denied to them on the basis of health-related surgical risk. Further to this aim, several specific objectives were identified, including:

  • Assessing whether the HIIT programme was suitable for the age group studied, through determining participants’ compliance with the protocol and their feelings towards it
  • Investigating whether participants exhibited improved aerobic fitness as a result of the programme, based on increases in both anaerobic threshold and VO2 max (a measure of the maximum rate of oxygen consumed during exercise)

Key Findings

In total, 28 participants (18 male, 10 female) with a mean age of 81.3 years completed the entire HIIT programme. A further four participants who began the programme failed to complete it, with two of these dropping out due to difficulty completing the exercises. Whilst HIIT was thus not suitable for everybody, those who completed the programme reported it as being highly acceptable. For example, 89% of individuals ‘Strongly agreed’ that HIIT was enjoyable, 86% ‘Strongly agreed’ that they would do it again, and 79% would recommend it to others.

During the 4-week control period prior to HIIT commencing, no changes in aerobic fitness were observed for participants. On the contrary, the HIIT programme resulted in significant increases in both anaerobic threshold and VO2 max. Although these increases were less than the researchers initially hoped for, they were comparable to those seen in younger populations without comorbidities and approached values considered clinically meaningful in the lead-up to an operation. Interestingly, the researchers also found a clear division between individuals who responded to the programme and those who didn’t. For example, improvements in aerobic fitness were observed in participants with urological but not colorectal cancer. These findings offer hope that it may be possible to identify individuals who will benefit from HIIT training over short timescales in the future.

This project formed the basis of a successful PhD thesis which was completed by one of the project collaborators, Dr James Blackwell. Several papers have been published as a result of the work, including this paper in the journal Medicine and Science in Sports and Exercise, with other manuscripts currently in preparation.