In this study, we compared postoperative exercise by 4 weeks and regular management in the postoperative control group, and both groups were effective in reducing the improvement of weight, BMI, NC, WC, and HC indicators. One study on postoperative weight change found that the initial phase of rapid weight loss usually enters in the first 3 months after bariatric surgery, followed by a slow phase and finally weight stabilization occurs, while the initial rapid weight loss is mainly due to a decrease in energy intake [13] .One of the reasons for the significant weight loss in both groups in this study may be due to the postoperative energy intake problem, which resulted in significant weight loss in both groups due to the intake being less than their own consumption. There was no statistical difference between the pre- and post-group changes in weight, BMI, NC, and WC in the two groups (P > 0.05), indicating that there was no statistical difference in the effect of the postoperative exercise intervention at 4 weeks versus the conventional postoperative management in the control group in reducing these indicators. Also, Metcalf [14] et al. obtained the same conclusion of this study by exercise intervention in postoperative patients, and although there was a significant decrease in weight change in the exercise and control groups, the improvement in the exercise group was also non superior to the control group (P > 0.05). In another study, Castello [15] et al. noted that postoperative obese women were randomized to the exercise group (n = 11) versus the control group (n = 10) after 3 months of aerobic training (50–70% HRmax) with 60 minutes of exercise 3 times per week. There was a significant decrease in weight, BMI and circumference after the intervention, and no statistical difference between the exercise and control groups in terms of weight and BMI reduction (P > 0.05). Meanwhile, the reduction in HC was significantly greater in the control group compared with the exercise group, and the control group was superior to the exercise group in terms of HC reduction (P < 0.05). The present study obtained the same results as this finding in terms of HC reduction, indicating that the control group was superior to the 4-week exercise intervention in terms of HC reduction. The reason for this may be due to the fact that the resistance training in this experiment not only improved the strength quality of the subjects but also may have delayed the decrease in HC, WHR is not only a measure of obesity but also an important way of judging body proportions. In this study, there was no significant change in WHR in the control group after 4 weeks (P > 0.05), while the 4-week exercise intervention caused a significant decrease in WHR (P < 0.05), and the change in the difference before and after WHR in the exercise group was statistically different from that in the control group (P < 0.01), indicating that the effect of exercise in reducing WHR was better than that in the control group. One of the main reasons may be due to the fact that the control group was superior to the 4-week intervention effect of exercise in reducing HC, and there was no statistical difference between the two groups in reducing WC, prompting the ratio of WC to HC in the exercise group to be smaller than that of the control, indicating that the 4-week exercise intervention was superior to the control group in reducing the effect of WHR and better improving body proportions.
The substantial weight loss in the control group at 4 weeks postoperatively was accompanied by a loss of muscle mass and protein catabolism. Although protein loss occurred after 4 weeks of exercise, the strength training in the exercise intervention may have had a better effect in improving strength and skeletal muscle synthesis, and the 4 weeks of exercise in this experiment contributed to the synthesis and relative improvement of skeletal muscle, which in turn alleviated and improved protein loss. The values of VFA measured after 4 weeks in both the exercise and control groups in this study were significantly lower (P < 0.01), with the 4-week exercise being greater in reducing VFA than the control group. In Bellicha [16] et al. provided evidence in the meta-analysis of their study that exercise training has an additional benefit on fat loss after bariatric surgery, which is also identical to the results of the present study. In terms of changes in muscle mass and skeletal muscle at 4 weeks postoperatively, the control group in this study showed a decreasing trend in the change in muscle mass before and after the 4-week exercise intervention, and the muscle mass remained on a decreasing trend (p > 0.05). However, the exercise group was lower than the control group in terms of the magnitude of the decline. Voican[17] et al. A study by Carnero [18] et al. reported that rehabilitation exercises after bariatric surgery are more important. Exercise exercise especially strength exercise will help to reduce muscle mass loss in postoperative patients after bariatric surgery. Both the exercise and control groups showed significant decreases in BMR posttest and were superior to the control group in delaying BMR decline (P < 0.05).Coen[19] et al. have shown that BMR is determined by total body weight, which is primarily non-total fat. Significant loss of muscle mass after weight loss surgery will decrease BMR levels. Both groups showed significant weight loss, while in terms of the magnitude of muscle loss, the control group showed greater muscle loss than the exercise group, prompting a statistical difference between the two groups, which in turn indicated that the exercise group had a better effect than the control group.
Glucose metabolic indexes improved improved in both control and exercise groups, with no statistical difference in the within-group difference changes in FINS, CP, HbA1c, HOMA-IR and ISI between the two groups (P > 0.05), while there was an advantage in improving FBG indexes in the control group (P < 0.01). In a study [20], 60 post-bariatric surgery patients were randomly assigned to a control combination exercise group (twice a week) and metrics were collected before surgery and at 6, 12 and 24 months after surgery, and significant decreases in glucose metabolism metrics were found in both the exercise and control groups. The effect of FBG, FINS, HbA1c and HOMA-IR by exercise intervention was not statistically different from the control group (P > 0.05).Campos [21] and Lin [22] and other studies have reported that weight loss surgery rapidly improves FBG and ISI in addition to significant weight loss, and that these effects occur in the post-surgical period and are modulated by multiple mechanisms. Within a few weeks after surgery, HOMA-IR also showed a decrease due to caloric restriction improving the ISI of the liver. The effect of FBG decrease was better in the control group than in the exercise group in this study (p < 0.01). Although bariatric surgery has a better effect on FBG reduction in patients, one study reported that one-third of patients undergoing laparoscopic gastric bypass and sleeve gastrectomy had symptoms of hypoglycemia [23] The reason for the significant glucose-lowering effect of the control group over the exercise group in lowering blood glucose in this study may be that four of the nine subjects in the control group in this study experienced hypoglycemia in the posttest FBG measurement after 4 weeks. In contrast, of the 8 subjects in the exercise group, only one subject developed a hypoglycemic condition. It also suggests that exercise may have a role in controlling the relative stability of FBG and improving hypoglycemia.
Dyslipidemia also contributes to the increased incidence of cardiovascular disease [24]. The control group in this study had highly significant reductions in TC and LDL-C levels after 4 weeks (P < 0.01) and no significant changes in TG levels (P > 0.05), and the exercise group also had significant reductions in all three of these indicators after 4 weeks of exercise. However, there was no significant change from the control group in the magnitude of reduction in TC, TG, and LDL-C. Kelley [25] et al. indicated that post-weight loss surgery was very effective in reducing LDL-C levels. However, exercise exercise did not add additional effect on LDL-C improvement. Another study showed [26] that the improvement in LDL-C after bariatric surgery may diminish the benefit of exercise when bariatric patients are in the first postoperative year of an active weight loss phase. For the reasons for the decrease in HDL-C in the control group, it has been shown that HDL-C levels change during weight loss and that weight loss usually increases lipoprotein lipase activity, especially after weight stabilization. However, during acute caloric restriction, the concentration of this enzyme decreases by 50%, contributing to the decline in HDL-C in the postoperative period [27, 28]. A study showed that in subjects with 30 minutes of supervised exercise training per session for 6 months, TC, LDL-C and TG levels decreased, while HDL-C levels tended to increase after exercise [29]. In Barter [30], a study indicated that patients after bariatric surgery experience low HDL-C levels and that exercise training at 6 months postoperatively has a favorable effect on increasing HDL-C levels.