The Effect of Exercise in Patients Awaiting Bariatric Surgery (BariPrehab)

The Effect of a Preoperative Exercise Programme on Cardiorespiratory Fitness, Resting Metabolic Rate and Autonomic Control in Patients With Severe Obesity Awaiting Bariatric Surgery

The aim of this project is to understand the impact of a four week preoperative exercise programme on fitness and metabolic rate and weight before surgery and weight after surgery. A single-site randomised trial at UCLH, recruiting patients awaiting bariatric surgery for obesity at UCLH, Whittington Health NHS Trust, or Homerton University Hospital NHS Foundation Trust. The investigators will measure fitness, metabolic rate, body weight/composition and grip strength in all participants, before and after a four-week supervised physical activity intervention. The investigators will follow each participant's journey through surgery and determine whether the exercise intervention led to differences between the weight of the two groups after surgery. The investigators will also interview participants about their participation in the study in regard to the planning of future studies.

The aim of this project is to understand the impact of a structured personalised 4-week exercise programme on resting fitness and metabolic rate in patients awaiting bariatric surgery for obesity. The hypothesis is that patients awaiting bariatric surgery who undertake a preoperative exercise programme will experience attenuated changes in functional capacity and metabolic rate compared with usual care (no exercise programme) along with alterations in autonomic control and medium-term postoperative weight loss. The investigators propose a randomised controlled trial that will recruit 70 patients with obesity scheduled for bariatric surgery at UCLH, Whittington Health NHS Trust, and Homerton University Hospital NHS Foundation Trust. Participants will be randomly assigned to either usual care (exercise advice only) or combination exercise intervention group, during a four-week lead up to surgery, on a 1:1 basis. Participants randomised to the intervention group will participate in 7 physiologist-led exercise sessions online and also be instructed to complete seven self-led 30-minute exercise sessions over the four-week intervention period. This equates to a total of 14 exercise sessions across the four-week (28 day) intervention. Additionally, participants will be encouraged to be physically active on as many days as possible, in bouts of 10-minutes or more. The programme is designed to meet the National Physical Activity Guidelines of at least 150 minutes of low-moderate or 75 minutes of vigorous PA per week, or a combination of the two. The investigators will measure physical fitness, metabolic rate, and how the heart responds to hormonal changes (the sympathetic nervous system) in all participants, before and after the four-week study period. The investigators will also follow each participant's journey through surgery and determine whether the exercise intervention led to differences between the two groups after surgery in terms of weight loss. The investigators will also interview participants about their participation in the study in regard to the planning of future studies. Baseline data collection will occur approximately six weeks prior to surgery as detailed below. Both groups will be invited to attend follow-up assessment at 4 weeks where they will undergo the same series of tests. Post-surgery, at 12 weeks and 24 weeks, participants will be invited to attend follow-up assessment where body weight will be measured. The post-operative testing visits will be aligned with scheduled hospital follow-up appointments. The total duration of participation will be approximately 32 weeks (six weeks preoperatively to six months (26 weeks) postoperatively).

A four-week preoperative physical activity intervention, involving a combination of supervised and unsupervised (live or pre-recorded), online exercise sessions. These sessions will be designed to meet the National physical activity guidelines (2020) of at least 150 minutes of low-moderate or 75 minutes of vigorous physical activity per week (or a combination of the two). The intervention will involve moderate intensity activities that aim to increase or maintain muscle strength (resistance training) as well as short bouts of vigorous aerobic exercise, using major muscle groups in the lower and upper body.

VO2 (at anaerobic threshold (AT) and peak exercise) using gas-analysed cardiopulmonary exercise testing.

Heart-rate variability measured via electrocardiogram (ECG), assessing the variability between heart beats at rest, resting heart-rate, and exercise heart-rate response

Participants satisfaction/acceptability of the mode of delivery and content of the intervention will be collected via semi-structured interviews. Participants will be asked how much they liked specific aspects of the program, and will answer using a 5-point Likert scale. They will also be asked to provide general feedback, and answers related to behaviour change using open-ended questions.

7-day physical activity patterns (sedentary time, low, moderate and vigorous physical activity) measured using accelerometer data

Inclusion Criteria: Adults, aged 18 and above. Patients enrolled in the UCLH, Homerton or Whittington Hospitals bariatric surgery program with BMI > 30 kg/m2 ≤5 % variation in body weight over preceding 3 months. Willing and able to comply with the trial protocol. Willing and able to provide written informed consent Male or Female Exclusion Criteria: Pregnant or lactating mothers. Weight over 180 kg (due to weight restrictions of equipment used). Current use of betablockade. Obstructive sleep apnoea requiring home ventilation assistance. Hypo/hyperthyroidism. Concurrent participation in other clinical intervention trial. Clinically significant medical co-morbidities (e.g. uncontrolled hypertension, unstable cardiovascular disease) that could place at risk of an adverse response to exercise. History of atrial fibrillation, unstable angina, acute coronary syndrome, congestive heart failure New York Heart Association class III-IV within the preceding 12 months.

Durey BJ, Fritche D, Martin DS, Best LMJ. The Effect of Pre-operative Exercise Intervention on Patient Outcomes Following Bariatric Surgery: a Systematic Review and Meta-analysis. Obes Surg. 2022 Jan;32(1):160-169. doi: 10.1007/s11695-021-05743-w. Epub 2021 Oct 20.

Sardeli AV, Komatsu TR, Mori MA, Gaspari AF, Chacon-Mikahil MPT. Resistance Training Prevents Muscle Loss Induced by Caloric Restriction in Obese Elderly Individuals: A Systematic Review and Meta-Analysis. Nutrients. 2018 Mar 29;10(4):423. doi: 10.3390/nu10040423.