Late bedtime is associated with lower weight loss in patients with severe obesity after sleeve gastrectomy.

BACKGROUND: Previous research has shown that sleep can play a role in obesity and weight loss. However, the association of sleep with weight loss in patients with severe obesity after bariatric surgery remains unexplored. We aimed to evaluate the role of sleep in weight loss evolution in a cohort of patients who underwent sleeve gastrectomy. METHODS: A cohort of 252 patients with severe obesity (75.7% women; age [mean ± SD] 47.7 ± 10.8 years; BMI 44.2 ± 5.9 kg/m2) was followed for 1 year after surgery. Anthropometric, biochemical, physical activity, sleep (bedtime, wakeup time, and sleep duration) and dietary intake variables were collected pre- and post-surgery (1 year). Linear and non-linear regression models were used to examine the associations between sleep variables and weight loss. Participants were grouped into 'early' and 'late' sleepers according to a bedtime threshold (before or after 24:00 h), and the differences in weight loss, physical activity, meal timing, and dietary intake between groups were studied. RESULTS: 1-h increments in bedtime were linearly associated with less excess weight loss (EWL) [-2.23%; 95%CI: -3.37; -0.70; p = 0.005] 1 year after the sleeve gastrectomy. Late sleepers lost less weight (-5.64% of EWL [95%CI: -10.11; -1.17]; p = 0.014) when compared to early sleepers and showed a higher energy intake after 21:00 h (8.66% of total energy intake [95% CI: 4.87; 12.46]; p < 0.001). CONCLUSIONS: Late bedtime is associated with less success of weight loss 1 year after the sleeve gastrectomy. Late sleepers consumed more of their calories closer to bedtime. Our results highlight the relevance of considering recommendations on bedtime and meal timing for patients after bariatric surgery.

Sleeve gastrectomy in patients with severe obesity restores circadian rhythms and their relationship with sleep pattern.

Advances in research have linked alterations of circadian rhythms with obesity. However, few studies have focused on the recovery of the circadian expression after a weight loss treatment. Our aim was to study the alterations of the circadian rhythmicity due to morbid obesity and the recovery of the circadian pattern after weight loss in a cohort of patients who underwent sleeve gastrectomy. For this purpose, 41 patients with severe obesity (75% women; age [mean (SD)] 49.7 ± 10 years; BMI 44.3 ± 6.2 kg/m2) were monitored before bariatric surgery and 9 months afterward. On both occasions, activity and wrist temperature were determined by actigraphy and were related with weight loss. Anthropometric, biochemical, and sleep-related variables, along with dietary intake and physical activity, were analyzed in relation with circadian rhythmicity. Results show significant differences in the circadian expression before and after 9 months of bariatric surgery, with more stable and less fragmented rhythms after weight loss. Moreover, only after surgery were the circadian variables associated to sleep timing and chronotype. The findings of this study indicate that weight loss treatment in patients with morbid obesity improves the circadian rhythm expression, and in such a way that it could be associated with better sleep quality. Moreover, it allows the recovery of the relationship between sleep patterns and circadian rhythm that was lost due to the obesity.