Post-bariatric surgical guidelines focus on a range of follow-up protocols that record and follow a patient’s glycaemic control, blood lipid profile, obstructive sleep apnoea, gastroesophageal reflux disease, body weight, etc. However, the role and importance of physical activity or exercise intervention in the follow-up trajectory is only mentioned to a limited extent, according to researchers from Belgium and France, even though an increase in physical activity/exercise intervention in post-operative patients is associated with several clear health benefits including bodyweight, fat mass, muscle mass and strength, physical fitness and bone mineral density (BMD).
Writing in the paper, ‘Towards Optimized Care After Bariatric Surgery by Physical Activity and Exercise Intervention: a Review’, published in Obesity Surgery, the authors explain why exercise and physical activity are important after surgery, how exercise should be prescribed (exercise programme characteristics) and monitored, and most importantly how to assess the benefits (physical fitness, muscle strength, fat mass and bone mineral density, etc.) of exercise during follow-up.
It has been well reported that patients with obesity or other chronic diseases benefits from physical exercise and that such exercise is independently related to a lower risk of complications, the need for hospitalisation and premature death. More specifically, the researchers noted that after bariatric surgery, there is clear evidence in the literature that exercise increases total energy expenditure, aids greater BMI reduction, prevents weight regain and significantly increases functional capacity (6-min walking test, 6MWT) or self-reported physical fitness. Improving overall physical fitness is prognostically more important than adiposity in patients with obesity, they write.
Nevertheless, the authors caution that post-surgery 10–28% of the total body weight loss has been attributed to decrements in muscle mass and muscle strength decline independently translates into a greater risk for premature death and loss of independence. Indeed, the prevalence of obesity sarcopenia is well recorded in the literature and is independently associated with various adverse outcomes (24% higher risk for premature death). Post-bariatric surgery, if significant reductions in muscle strength are observed, healthcare professionals should assess if the patient is suffering from severe muscle wasting. Finally, bariatric surgery is also associated with significant reductions in BMD thereby increasing the risk of bone fractures. Therefore, the authors emphasise the importance of continually assessing physical activity and fitness, muscle strength and mass, and BMD, in post-bariatric patients.
Assessing and monitoring exercise
There are well-known discrepancies between self-reported physical activity questionnaires and studies assessing physical activity by means of objective tools after bariatric surgery – the former usually reports improvements vs. the latter which usually report no improvements. Therefore, if one wishes to measure post-bariatric physical activity, the authors note that there is some evidence in the literature that accelerometery may be more beneficial than pedometers (lower intense exercise could lead to inaccurate registration by pedometers).
Interestingly, post-surgical improvements in walking capacity do not seem to be associated with improvements cardiorespiratory or muscular function but linked to weight loss. As a result, poor cardiorespiratory and muscle function could still be a factor in present post-bariatric surgery patients. A functional test such as the 6MWT can be useful tool, preferably in a corridor, as musculoskeletal symptoms are present during walking activities and it is necessary to see if these symptoms change during the weight loss period.
If assessing exercise capacity, the authors note that due to significant post-operative changes in body weight they do not advise dividing VO2peak by body weight (as ml/min/kg), however, dividing VO2peak by fat-free mass can be considered. Once the body weight stabilised, several tests can be carried out including aerobic power index test, although clinicians should always consider patient’s medication and their suitability for such tests.
To assess muscle strength, hand grip strength has its merits, although the authors point to some evidence that it is not sensitive to measure post-bariatric strength changes, and muscle groups that are targeted during the exercise intervention would be a preferable assessment method (dynamometry testing in the hospital or out of hospital 1-repetition maximum (1RM) training intensity formula) to evaluate muscle strength changes over time.
Body composition is directly related to exercise capacity and the authors recommend dual x-ray absorptiometry scan to monitor lean tissue mass and bone mineral density changes. If not available, they state that tetrapolar bioelectrical impedance analysis may be used if the patient is hydrated.
Types of post-op exercise
The authors caution that there are few recommendations in the guidelines for how to exercise post-operatively, but they add the exercise should be designed to specifically affect fat mass, muscle mass, endurance exercise capacity and BMD.
There is some evidence to suggest that there is greater adherence to structured/supervised exercise intervention post-surgery, as opposed to usual-care follow-up, especially if the patient takes part in pre-operative exercise training. Moreover, it is recommended that:
- the weekly endurance exercise volume should be increased significantly as exercise or physical activity with smaller total exercise volumes fails to maximise post-op weight loss
- daily physical activity should be permanently increased to minimise body weight regain
- a combination of strength training with sufficient intake of proteins and amino acids can stimulate muscle mass gain/preserve lean tissue mass
“As uptake and long-term adherence to an active lifestyle are crucial for long term beneficial effects, future research should look into the use of telemonitoring or the adoption of lifestyle applications to increase levels of physical activity,” the authors write. “…the current evidence collectively indicates that care after bariatric surgery could be improved significantly by the additional incorporation of health-related fitness components assessments and physical activity and exercise interventions.”
This article was authored by Dominique Hansen, Lieselot Decroix, Yves Devos, David Nocca, Veronique Cornelissen, Bruno Dillemans and Matthias Lannoo.