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.

A multi-site randomised trial sponsored by UCL, recruiting patients awaiting bariatric surgery for obesity at University College London Hospital (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 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 (fitness) and metabolic rate compared with usual care (no exercise programme) along with alterations in autonomic control.

The investigators propose a randomised controlled trial that will recruit 48 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 7 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 interview participants about their participation in the study in regard to the planning of future studies.

Baseline data collection will occur at least 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. The total duration of participation will be approximately 4 weeks.

Inclusion Criteria:

1. Adults, aged 18 and above.
2. Patients enrolled in the UCLH, Homerton or Whittington Hospitals bariatric surgery program with BMI > 30 kg/m2
3. ≤5 % variation in body weight over preceding 3 months.
4. Willing and able to comply with the trial protocol.
5. Willing and able to provide written informed consent
6. Male or Female

Exclusion Criteria:

1. Pregnant or lactating mothers.
2. Weight over 180 kg (due to weight restrictions of equipment used).
3. Current use of betablockade.
4. Concurrent participation in other clinical intervention trial.
5. Clinically significant medical co-morbidities (e.g. uncontrolled hypertension, unstable cardiovascular disease) that could place at risk of an adverse response to exercise.
6. History of atrial fibrillation, unstable angina, acute coronary syndrome, congestive heart failure New York Heart Association class III-IV within the preceding 12 months.

Summary format only, Access to IPD will be reviewed on a case-by-case basis following requests.