Physical activity for optimising and sustaining long-term bariatric surgery outcomes

Obesity levels are increasing worldwide, and in the United Kingdom the prevalence of overweight and obesity is amongst the highest in the developed world. Obesity is associated with reduced physical function and health-related quality of life, as well as an increased risk of co-morbidities such as type 2 diabetes and hypertension. As a result of high levels of morbid obesity and a failure of conventional methods of weight loss, more people are resorting to invasive weight loss techniques such as bariatric surgery. Bariatric surgery combined with lifestyle modification is currently the most successful weight loss intervention for the treatment of obesity and its associated co-morbidities. However, weight regain is becoming more apparent, generally occurring between 12 and 24 months after surgery. Weight regain is generally attributed to the failure of individuals to adopt or maintain the necessary lifestyle changes. The most common factors leading to weight regain after bariatric surgery are insufficient exercise and returning to pre-operative eating behaviours. Increasing physical activity after surgery positively affects weight loss and physical function outcomes; therefore, adopting an active lifestyle is fundamental. This thesis combines three research studies which collectively provide evidence for understanding the importance of physical activity for optimising physical function and facilitating the prevention of weight regain. Study one is a systematic review and meta-analysis which assessed pre to post-operative changes in physical activity behaviour and physical function outcomes among obese adults receiving bariatric surgery. This demonstrates improvements in objective and self-reported activity and function by 12 months. Study two is an analysis of body mass, co-morbidity and physical function data from pre to post bariatric surgery. This retrospective NHS dataset analysis aimed to identify if and when weight regain occurs, the proportion of co-morbidity resolution, and physical function patterns in patients after bariatric surgery. Weight loss patterns indicate weight stability from 12 to 24 months and weight regain 24 months post-surgery. Study three is a randomised controlled trial, The MOTION Study, which examined the effect of a 12 week exercise intervention on physical function and body composition in patients 12-24 months post bariatric surgery. This trial also examined maintenance of effects at six months. Findings suggest that implementing exercise at the point of weight regain is effective, notably for improving physical function and body composition in this population. This thesis therefore contributes to advancing the understanding of the role of physical activity in enhancing long-term outcomes after bariatric surgery and to informing future post-operative bariatric care

The effects of supervised exercise training 12–24 months after bariatric surgery on physical function and body composition: a randomised controlled trial

Background:Bariatric surgery is effective for the treatment of stage II and III obesity and its related diseases, although increasing evidence is showing weight regain ~12–24 months postsurgery. Weight regain increases the risk of physical function decline, which negatively affects an individual's ability to undertake activities of daily living. The study assessed the effects of a 12-week supervised exercise intervention on physical function and body composition in patients between 12 and 24 months post bariatric surgery.Methods:Twenty-four inactive adult bariatric surgery patients whose body mass index remained ⩾30 kg m2 12 to 24 months post surgery were randomised to an exercise intervention (n=12) or control group (n=12). Supervised exercise consisted of three 60-min gym sessions per week of moderate intensity aerobic and resistance training for 12 weeks. Control participants received usual care. The incremental shuttle walk test (ISWT) was used to assess functional walking performance after the 12-week exercise intervention, and at 24 weeks follow-up. Measures of anthropometric, physical activity, cardiovascular and psychological outcomes were also examined. Using an intention-to-treat protocol, independent t-tests were used to compare outcome measures between groups.Results:Significant improvements in the exercise group were observed for the ISWT, body composition, physical function, cardiovascular and self-efficacy measures from baseline to 12 weeks. A large baseline to 12-week change was observed for the ISWT (exercise: 325.00±117.28 m; control: 355.00±80.62 m, P<0.001). The exercise group at 24 weeks recorded an overall mean improvement of 143.3±86.6 m and the control group recorded a reduction of −32.50±75.93 m. Findings show a 5.6 kg difference between groups in body mass change from baseline to 24 weeks favouring the exercise group.Conclusions:A 12-week supervised exercise intervention led to significant improvements in body mass and functional walking ability post intervention, with further improvements at the 24-week follow-up