Short-Term Effects of Weight Loss after Bariatric Surgery on Respiratory and Skeletal Muscles’ Strength

Background: Bariatric surgery leads to weight loss and body fat percentage reduction, but patients are prone to lean tissue loss which itself reduces the quality of life, and increases the risk of deatand h. This study evaluated the effects of bariatric surgery and changes in Fat Mass (FM) and Fat-Free Mass (FFM) on the respiratory and skeletal muscles’ strength three months after bariatric surgery. 
Methods: After obtaining demographic information, anthropometric measurements and body composition analysis, including Body Mass Index (BMI), FM, FFM,  Percent Body Fat (PBF), handgrip isometric force, respiratory muscle forces and spirometry volumes, were assessed before and three months after bariatric surgery in 50 men and women undergoing this surgery. 
Results: Weight, BMI, FM, PBF and FFM isometric muscle force were decreased significantly. In contrast, respiratory muscle forces and respiratory volumes were increased significantly three months after the surgery. Reduction in FFM 3 months after the surgery did not lead to a change in respiratory muscle strength (p-values≥0.05). 
Conclusion: According to our findings, FM and FFM along with weight and BMI decrease significantly after bariatric surgery. These alternations were accompanied by a significant increase in respiratory muscle strength but were not correlated with handgrip muscle force changes.