Clinically significant weight loss is associated with health benefits for overweight and obese adults. Participation in adequate amounts of physical activity is critical for weight maintenance. However, the recommended amount of physical activity needed to promote weight maintenance is based primarily on retrospective studies that quantified physical activity levels through questionnaires which tend to overestimate physical activity levels. In addition, the present literature has provided little data on the impact of these physical activity levels on cardiovascular and diabetes risk factors, which may have equal or more clinical importance than weight changes. The Prescribed Exercise to Reduce Recidivism After Weight Loss-Pilot (PREVAIL-P) study will evaluate the effect of aerobic exercise training amount on weight maintenance following clinically significant weight loss in overweight and obese adults (BMI 25–40 kg/m 2 ) age 30–65 years. Participants (N = 39) will complete a 10-week OPTIFAST® weight loss program with supervised aerobic exercise training. Individuals who achieve ≥7% weight loss from baseline will be subsequently randomized to levels of aerobic training consistent with physical activity recommendations (PA-REC) or weight maintenance recommendations (WM-REC) for 18 additional weeks. The primary outcome of the PREVAIL-P study will be change in weight from the completion of OPTIFAST® program to the end of the study. Notable secondary measures include changes in clinically relevant cardiometabolic risk factors between study groups (e.g. blood lipids concentrations, oral glucose tolerance, arterial stiffness). This pilot study will be used to estimate the effect sizes needed for a randomized controlled trial on this topic.

SummaryArterial stiffness is improved by weight loss. However, no data exist on the impact of aerobic exercise levels on arterial stiffness during weight maintenance. Adults who were  overweight or with obesity (N = 39) participated in a 10‐week weight loss program. Participants who achieved ≥7% weight loss were randomized to aerobic training at the minimum physical activity guidelines (PA‐REC, 550 MET min/week) or weight maintenance guidelines (WM‐REC, 970 MET min/week) for 18 additional weeks. Arterial stiffness (carotid‐to‐femoral pulse wave velocity [cfPWV], augmentation index normalized for 75 beats/min [AIX75]) and blood pressure [aortic and brachial]) were assessed at baseline, the end of the weight loss phase (week 10), and follow‐up (week 28). There was a reduction in cfPWV in participants who met the weight loss goal (−0.34 m/s, p = .02) and approached significance for the entire sample (p = .051). Similarly, there were reductions in AIX75, brachial blood pressure, and aortic blood pressure (p < .05) in the full sample. In the weight maintenance phase, no differences were observed between the PA‐REC and the WM‐REC groups for change in arterial stiffness or blood pressure (p > .05). However, changes in cfPWV were independently associated with changes in LDL (r2: 0.45, p = .004) and exercise intensity (r2: 0.17, p = .033). Aerobic exercise level at the minimum physical activity guidelines or weight maintenance guidelines does not affect the change in PWV or the change in cfPWV after clinically significant weight loss. However, interventions which limit increases in LDL cholesterol and promote high‐intensity aerobic exercise may prevent increases in stiffness during weight maintenance.

To investigate relationships between weight loss and weight loss maintenance with cardiac autonomic function and exercise in obesity, 39 adults (45.7±10.7 years; BMI: 34.2±3.4 kg/m2) participated in a 10-week, medical weight loss program combined with aerobic exercise. A subset (n=18) participated in an aerobic exercise weight loss maintenance program (550 or 970 MET minutes/week) for 18 additional weeks. Primary outcomes included markers of cardiac autonomic function assessed by heart rate variability (HRV) (i.e., SDNN, RMSSD, HFln). Following weight loss, we observed significant improvements for SDNN (48.2±19.1 vs. 55.1±25.9 ms, p=0.03) RMSSD (37.7±24.0 vs. 47.9±29.1 ms, p=0.002), and HFln (5.88±1.34 vs. 6.32±1.28 ms, p=0.001). Regression analyses showed fasting insulin concentration predicted 24% and 27% of the variance in RMSSD (r2=0.236, p=0.007) and HFln (r2=0.274, p=0.004), respectively. Following weight loss maintenance, no significant changes in HRV were observed. Changes in LDL (r=–0.54, p=0.04) and non-HDL (r=–0.77, p=0.001) were inversely associated with RMSSD changes. Clinically significant weight loss via caloric restriction and aerobic exercise improved HRV markers of cardiac vagal modulation. Following weight loss maintenance, we did not observe any further changes in HRV. Thus, our data suggests commonly prescribed exercise volumes contribute to maintenance of parasympathetic modulation following medical weight loss programming and exercise.

PURPOSE:It has been suggested that cardiorespiratory fitness (CRF) is associated with favorable health outcomes independent of comorbidities, including obesity. However, relatively few studies have assessed the association between CRF and mortality risk in obese women. Thus, in the present work we aimed to assess the relationship between CRF and risk of mortality among obese women. METHODS: Female (N=39,556) US Veterans completed a symptom-limited exercise treadmill test (ETT) between 1999-2020 using the Bruce Protocol. Of those 28,681 were classified as obese based on body mass index (BMI) ≥30.0 kg/m 2 criteria. We established four CRF categories based on age-specific quartiles of peak metabolic equivalents (METs) achieved: Least-Fit (n=8,005), 475), 905) and 296). Multivariate Cox models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for death events across CRF categories. RESULTS: During the follow-up period (median=8.0 years), 1,174 women died (48.1 events/10,000 person-years of observation). Body weight in those within the Least-Fit CRF category was significantly higher when compared to women in the High-Fit category (90±17 vs. 78±11 kg, p<0.001). After adjustments for age, race, hypertension, diabetes, smoking status, major adverse cardiovascular event, breast or lung cancer and heart failure, mortality risk was 18% lower for each 1-MET increase in exercise capacity (HR: 0.82, 95% CI: 0.79-0.84). When CRF categories were considered, comparisons to the Least-Fit category (referent) revealed a progressive decline in risk with higher CRF status. Specifically, mortality risk was 32% lower for Low-Fit women (HR: 0.68, 95% CI: 0.62-0.76), 55% lower (HR: 0.45, 95% CI: 0.38-0.53) for Moderate-Fit, and 68% lower (HR: 0.32, 95% CI: 0.26-0.41) for those in the High-Fit category. CONCLUSIONS: In obese women, CRF was inversely associated with mortality risk and followed a dose-response pattern. These findings support the concept that adequate physical activity that leads to increased CRF is protective against premature mortality in obese women.

Objective: The OPTIFAST diet has known effects for weight loss, but little data exists on the effects of the diet on arterial stiffness. Methods: Overweight and obese (BMI: 34.5 + 4.0) adults (N=17) participated in a 10-week OPTIFAST™ weight loss program and supervised aerobic exercise training (50%-75% VO 2 max). The diet consisted of OPTIFAST meal replacement products with a goal of reducing total caloric intake to 800 kcals/day and attending a weekly weight management class. Aerobic exercise was performed 3 times per week and the exercise volume was progressed from 300 to 700 MET mins. per week at an intensity of 50%-75% VO2 max. The goal of study participants was to achieve a 7% weight loss. Carotid-to-femoral pulse wave velocity, blood pressure (aortic and brachial), vascular age, augmentation index and blood samples were measured in the morning after an overnight fast at baseline and follow-up. A paired t-test was performed to evaluate the change in outcomes variables. Results: The mean percent weight loss in the sample was 9.0% (-8.5 kg), with 83.3% of participants achieving 7% weight loss (94.1% achieving ≥5%). The adherence to the exercise program was 94.9% and attendance in the weight loss classes was 81.8%. There was a reduction in pulse wave velocity (-0.44 m/s, p=0.030), aortic systolic blood pressure (-10.5 mmHg, p<0.001), aortic diastolic blood pressure (-7.8 mmHg, p<0.001), brachial systolic blood pressure (-11.2 mmHg , p<0.001), brachial diastolic blood pressure (-7.7 mmHg, p<0.001), vascular age (-13.4 yrs., p=0.008), resting heart rate (-4.7 bpm, p=0.005), and augmentation index (-7.5%, p=0.008) after the intervention. Change in resting heart rate from the intervention was associated with improvements in augmentation index (r=0.60, p=0.010) and approached significance for pulse wave velocity (r=0.45, p=0.07). Weight loss was associated with reduction in augmentation index (r= 0.56, p=0.02), but not change in PWV (r=-0.07, p=0.78). Changes in other cardiometabolic risk factors (e.g. glucose, insulin, lipids, and body fat) were not associated with improvements in arterial stiffness or blood pressure measures (all ps>0.05). Discussion: A hypo-caloric dietary program in combination with aerobic exercise training improves arterial stiffness, aortic blood pressure, and brachial blood pressure in overweight and obese adults An important limitation of the present study is that we cannot separate the health benefits of the diet from the exercise.