Both relative muscle strength and physical performance improved substantially in patients following Roux-en-Y gastric bypass (RYGB) surgery, thus suggesting that RYGB may improve the ability to perform activities of daily living, according to study findings reported in The Journal of Clinical Endocrinology & Metabolism.

Obesity is a chronic multifactorial disease and in addition to increasing the risk for metabolic and cardiovascular disease, it is associated with impaired skeletal muscle quality, poor physical performance, and higher risk for functional decline. It has been suggested that bariatric surgery and the resulting weight loss could potentially lead to improvements in these areas despite loss of muscle mass. In the current study, researchers examined changes in body composition, muscle strength, and physical performance in 47 adults. Anthropometric data, handgrip strength, physical activity, and physical performance were measured prior to RYGB and then and 6 and 12 months after the procedure.

The cohort achieved a substantial 12-month decrease in total body weight (30% ± 7%), fat mass (-49% ± 12%), and total lean mass (-14% ± 6%), but mean absolute muscle strength also decreased by 2.6 kg ± 5.4 kg (P <.001). However, relative muscle strength increased by 32% ± 25% for strength/body mass index and 9% ± 20% for strength/appendicular lean mass (P <.01 for both). In addition, the participants achieved statistically and clinically significant postoperative improvements in all physical performance measures including gait speed by >0.1 m/s (P <.01) and a decrease in the walk time for a 400-meter distance by almost a full minute (from 5.3 min ± 0.6 min to 4.4 min ± 0.7 min; P <.01).

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Changes in physical activity were varied and showed no consistent patterns from pre-RYGB to 6 or 12 months postsurgery. The researchers noted that data for physical activity were self-reported in questionnaires and possibly misrepresented or exaggerated by participants.

“The magnitude of the physical performance improvements is clinically significant and suggests that RYGB improves a person’s ability to perform activities of daily living,” wrote the researchers.

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Alba DL, Wu L, Cawthon PM, et al. Changes in lean mass, absolute and relative muscle strength, and physical performance after gastric bypass surgery. J Clin Endocrinol Metab. 2019;104(3):711-720.