A somewhat limited number of published intervention studies in post-surgical bariatric patients have investigated physical activity in this cohort. However, very few have investigated the physical activity intervention as a randomized controlled trial or have studied weight loss as a post-surgical outcome. For example, skeletal muscle lipid oxidation, but not body weight was assessed in post-bariatric surgery patients following a 10-day exercise training program [71
]. A 12-week exercise training program examined heart rate kinetics and physical function, but not body weight or body composition, in women following gastric bypass surgery [72
]. Additionally, neither of these studies compared a control/usual care group with an exercise training group. However, findings from these studies can be forth telling by describing the feasibility of implementing the exercise training program in this cohort, as well as retention rates and attendance to sessions.
In a nonrandomized, retrospective review of medical records, participation in an individual personal trainer exercise program in post-surgical patients lead to greater weight loss at 12-months, but body weight at 36-months did not differ between those that attended at least one personal trainer session compared to those that did not attend any of these sessions [74
]. This provides preliminary evidence that participation in a post-surgical exercise program can be beneficial for short-term weight loss as shown by an additional 6 kg loss in these patients at 12-months.
In a recent multi-site prospective randomized clinical trial, a total of 128 men and women who had gastric bypass surgery were randomized into a 6-month exercise training program or a health education control group [75
], with an average of nearly 80 days between surgery and intervention initiation date. The exercise training was described as semi-supervised and moderate intensity with a goal of 120 minutes/week of moderate-to-vigorous activity. There was less than a 10% drop out of randomized participants from both intervention groups in the 6-month study. The mean amount of weekly exercise time for the exercise group was 147 minutes measured over the second half of the study; moreover, two-thirds of the participants in this group performed at least 120 minutes of exercise per week with a mean in this subset of 185 minutes. Not including those that dropped out, there were 16 participants in the exercise training group who did not achieve the intervention goal, and they averaged fewer than 60 minutes of activity a week during the final 3-months of the study. In this nonadherence group, five had health issues not related to the intervention, two lived an extensive distance from the exercise facility, and 9 had no obvious explanation for nonadherence. For body weight and body composition, there were expected changes between baseline and post intervention, but there were no intervention group effects.
In a small (n=8) nonrandomized study of women, participation in a short-term (8-week) lifestyle intervention that included behavior modifications for physical activity and nutrition resulted in a greater percent of weight loss than historical controls from 3-12 months post-surgery (12.2% vs. 5.1%) [76
]. Moreover, physical function, participation in strenuous intensity exercise, dietary intake, and quality of life all improved with participation in the intervention program. This intervention was initiated when patients were 3-6 months post-surgery. The exercise program was a once-a-week facility based program for 60 minutes that was led by either an exercise specialist or physical therapist. There was a combination of resistance training and cardiovascular exercise at these sessions. Additionally, patients were instructed to exercise at home for at least 30 minutes a day for 5 days a week with resistance bands and walking exercise, with activity diaries kept by participants to verify adherence to the intervention.
Both strength and endurance training was included in a pilot, nonrandomized trial of post gastric bypass surgery patients [77
]. Participants were able to choose whether they wanted in the exercise trained or the notrained group. A total of 19 individuals were tested at baseline (10 in the trained and 9 in the untrained groups); there were 2 dropouts from each so that the final sample size with 8 in the trained and 7 in the untrained group. The trained group met 3 times a week for 12 weeks, 75 minutes each session. There were 25 minutes of strength training and 30 minutes of endurance training each session. The final goal for the resistance training was 3 sets of 10 repetitions at 75% of the 1 repetition maximum for both elbow and knee flexion and extension. The endurance training was a mix of cycling, walking and stepping at 60% of heart rate reserve. At the end of the intervention, both groups lost similar amounts of weight and had similar changes in body composition with a loss of both fat mass and fat-free mass. Benefits from the exercise training program were apparent compared to the untrained patients with regards to muscle strength, but not for peak exercise capacity or physical function.
In a randomized trial of Hispanic Americans (n=144), a 12-week comprehensive nutrition education program was initiated at 6-months post gastric bypass surgery with weight loss and physical activity levels being the primary outcomes of this study [78
]. Participants met in a group setting every-other-week for 6 sessions, 90 minutes per session. Only one of the sessions dealt specifically with physical activity as a way to assist with weight loss and weight loss maintenance. Compared to the noncomprehensive approach intervention, those in the comprehensive program lost more excess weight (80% vs. 64%) at 12-months, and they participated in more minutes of physical activity per week. At the initial assessment that occurred 6-months post-surgery, 74% of participants reported engaging in some type of physical activity. After the 6-month intervention, 82% of the comprehensive group and 67% of the noncomprehensive reported regularly engaging in exercise, with walking the most frequent activity. The mean time of exercise increased by 14 minutes/week in the active intervention group, whereas the comparison group decreased their level of activity by 4 minutes/week. This study suggests that a very mild promotion of a comprehensive approach for weight loss in post-surgical patients can have slight positive effects on physical activity behaviors and weight loss, even after the end of the group intervention in this ethnic specific cohort.
Shah et al. tested the feasibility and effect of a 12-week high-volume exercise program in a randomized controlled trial design in post bariatric surgery patients [79
]. The exercise goal was to expend at least 2,000 kcals/week by weeks 4-12 in moderate-intensity exercise (60-70% of maximal oxygen consumption). Participants were randomized to the progressive exercise training program (n=21) or a control group (n=12). The exercise participation goal was to exercise at least 5 days a week, with at least 1 or 2 sessions occurring in the fitness facility. Approximately one-third of the exercise group performed all their exercise sessions at the facility. The energy expenditure was estimated from the physical activity diary kept by participants. The attrition rate was 33% (4 out of 12 dropped out) for the control group and 24% (5 out of 21 dropped out) in the exercise group. About 50% of the participants in the exercise group achieved the 2,000 kcal/week energy expenditure goal at 12-weeks, with more than 80% reaching an expenditure of 1,500 kcals/week from moderate-intensity exercise. Consistent with these results, step counts increased in the exercise group from 5,500 at baseline to almost 10,000 at 12-weeks, with minimal change in the control group. Also maximal oxygen consumption improved from 17.4 ml/kg/min to 19.2 ml/kg/min for the exercise group, with no change seen in the control group. As expected, both groups showed significant changes in body weight and body composition, but noteworthy, there were no differences between groups. This feasibility study showed some success in having about 50% of patients achieve the exercise goal, and the approximately 10% improvement in cardiovascular fitness is related to lower mortality [80
There is rationale for inclusion of a resistance training exercise program in post bariatric surgery patients, as it is hypothesized to attenuate the loss of fat-free mass during the calorie-restricted weight loss period [81
], as well as to increase strength for improved physical function [77
]. In a nonrandomized pilot study testing a 12-week resistance training program in post bariatric surgery patients (n=19), body composition, body weight, and physical fitness (strength, cardiorespiratory fitness) were assessed in patients who started the exercise program within the first year after bariatric surgery [86
]. The 60-minute/day small group (n=5) training program occurred twice a week for the first 6-weeks and then three times a week for the last 6-weeks. The training included was heavily based on resistance training (45 minutes) and minimal cardiovascular training (10 minutes). All major muscle groups were targeted with the 8-10 stations. The workout goal was 3 sets of 8-12 repetitions at each station with only 60 seconds rest between sets and stations. This intervention achieved a high rate of adherence as patients participated in 84% of the training sessions, with no adverse events occurring. There were no differences between those participating in the training group and the usual care group with regards to body weight or body composition assessments. However, the training did result in improved function and fitness. This study was limited in the timing of the initiation of the intervention was diverse after surgery. The significant heterogeneity in the rate of weight loss during this period would likely influence the impact of different modalities of exercise training on body composition.