Determinants of Cardiorespiratory Fitness After Bariatric Surgery: Insights From a Randomised Controlled Trial of a Supervised Training Program.

BACKGROUND: Severely obese patients have decreased cardiorespiratory fitness (CRF) and poor functional capacity. Bariatric surgery-induced weight loss improves CRF, but the determinants of this improvement are not well known. We aimed to assess the determinants of CRF before and after bariatric surgery and the impact of an exercise training program on CRF after bariatric surgery. METHODS: Fifty-eight severely obese patients (46.1 ± 6.1 kg/m2, 78% women) were randomly assigned to either an exercise group (n = 39) or usual care (n = 19). Exercise training was conducted from the 3rd to the 6th months after surgery. Anthropometric measurements, abdominal and mid-thigh computed tomographic scans, resting echocardiography, and maximal cardiopulmonary exercise testing was performed before bariatric surgery and 3 and 6 months after surgery. RESULTS: Weight, fat mass, and fat-free mass were reduced significantly at 3 and 6 months, without any additive impact of exercise training in the exercise group. From 3 to 6 months, peak aerobic power (V̇O2peak) increased significantly (P < 0.0001) in both groups but more importantly in the exercise group (exercise group: from 18.6 ± 4.2 to 23.2 ± 5.7 mL/kg/min; control group: from 17.4 ± 2.3 to 19.7 ± 2.4 mL/kg/min; P value, group × time = 0.01). In the exercise group, determinants of absolute V̇O2peak (L/min) were peak exercise ventilation, oxygen pulse, and heart rate reserve (r2 = 0.92; P < 0.0001), whereas determinants of V̇O2peak indexed to body mass (mL/kg/min) were peak exercise ventilation and early-to-late filling velocity ratio (r2 = 0.70; P < 0.0001). CONCLUSIONS: A 12-week supervised training program has an additive benefit on cardiorespiratory fitness for patients who undergo bariatric surgery.

Validation and Cardiorespiratory Response of the 1-Min Sit-to-Stand Test in Interstitial Lung Disease.

PURPOSE: To assess the 1-min sit-to-stand test (1STS) test-retest reliability and construct validity and its associated cardiorespiratory response in comparison to the 6-min walk test (6MWT) and symptom-limited cycling cardiopulmonary exercise test (CPET) in people with interstitial lung disease (ILD). METHODS: Fifteen participants with ILD performed two 1STS tests, a 6MWT and a CPET. The three tests were administered on three separate visits, and cardiorespiratory parameters were continuously recorded during the tests. RESULTS: The number of repetitions during both 1STS tests was 22 ± 4 and 22 ± 4 (mean difference of 0.53 ± 2.00 repetitions, P = 0.32) with an intraclass correlation of 0.937 (95% confidence interval, 0.811-0.979]) and a minimal detectable change of 2.9 repetitions. The number of 1STS repetitions was highly correlated with the 6MWT distance (r = 0.823, P < 0.001) and with the peak cycling power output expressed in % predicted values (r = 0.706, P < 0.003). Oxygen consumption (V˙O2) peak during the 1STS reached 83% and 78% of V˙O2 peak during 6MWT and CPET, respectively. Peak 1STS HR, minute ventilation (V˙E,), V˙O2 values, as well as nadir SpO2 were achieved during the recovery phase of the test, whereas peak 6MWT and CPET HR, V˙E, V˙O2 and nadir SpO2 always occurred at the end of the test. The three tests elicited a similar fall in SpO2 ranging between 8% and 12%. Symptom scores after the 1STS were similar to those seen at the end of the 6MWT but lower than those of CPET. CONCLUSIONS: The 1STS showed excellent test-retest reliability in patients with ILD in whom it elicited a substantial, but submaximal cardiorespiratory response. Our data also support the construct validity of the 1STS to assess functional exercise capacity in patients with ILD and to detect exercise-induced O2 desaturation.

Safety of Blood Glucose Response Following Exercise Training After Bariatric Surgery.

INTRODUCTION: Safety of exercise training in relationship with the risk of hypoglycemia post-bariatric surgery is unknown. OBJECTIVE: To evaluate the safety and magnitude of changes in blood glucose levels during exercise training following bariatric surgery. MATERIAL AND METHODS: Twenty-nine severely obese patients undergoing either sleeve gastrectomy (SG) (n = 16) or biliopancreatic diversion with duodenal switch (BPD-DS) (n = 13) were prospectively enrolled. Three months after surgery, patients participated in a 12-week supervised exercise training program, (35-min aerobic training with a 25-min resistance exercises) three times a week. Capillary blood glucose (CBG) levels were measured immediately before and after each exercise session. RESULTS: Seven patients (24%) had type 2 diabetes before surgery (mean duration: 10 years); four patients still have type 2 diabetes 3 months post-bariatric surgery. A total of 577 exercise training sessions with CBG monitoring were recorded. Only seven sessions (1.2%) were associated with an episode of asymptomatic hypoglycemia (CBG ≤ 3.9 mmol/L). Patients with type 2 diabetes at baseline showed a larger decrease in CBG with pre-exercise CBG being between 6.1 and 8.0 mmol/L (- 1.6 ± 1.2 vs. - 1.1 ± 0.9 mmol/L, p = 0.02). BPD-DS patients with CBG ≥ 6.1 mmol/L showed higher reduction in CBG following exercise vs. SG patients (- 1.7 ± 1.0 vs. - 1.1 ± 1.1 mmol/L; p < 0.001 and - 4.3 ± 1.0 vs. - 2.2 ± 1.4 mmol/L, p < 0.001, respectively). CONCLUSION: Three months after bariatric surgery, exercise training program in patients without and with type 2 diabetes is safe, and is associated with a desirable glycemic profile, with few episodes of asymptomatic hypoglycemia.

How to choose and use bariatric surgery in 2015.

Severe obesity is associated with increased morbidity and mortality and represents a major health care problem with increasing incidence worldwide. Bariatric surgery, through its efficacy and improved safety, is emerging as an important available treatment for patients with severe obesity. Classically, bariatric surgery has been described as either a restrictive or a hybrid surgery, which is a combination of restriction and malabsorption. For most severely obese patients, bariatric surgery results in the remission of major obesity-related comorbidities including type 2 diabetes mellitus, sleep apnea, hypertension, and dyslipidemia. Thus, bariatric surgery reduces cardiovascular risk burden, and overall mortality risk. Early complications (< 30 days) after bariatric surgery were reported to be < 10% and tend to be lower in restrictive surgeries compared with hybrid surgeries. Most common early complications reported are gastric and anastomosis leak (1.6%-5.1%), bleeding (0.5%-3.5%), and pulmonary embolism (0.2%-1%). Long-term complications (> 30 days) might differ depending on the type of bariatric surgery. According to the type of surgery and the type of study, the 30-day operative mortality rates differ from 0.1% to 1.2%. Studies on postoperative outcomes, investigations on weight loss physiology, and mechanism of action after bariatric surgery provide a better understanding of the bariatric surgery metabolic benefits. In this article, we present an overview of bariatric procedures with their effects, including risks and benefits, on the severely obese patients' health. It provides evidence to support surgical treatment of severe obesity to achieve cardiovascular disease risk reduction in severely obese patients.