Effect of Sleep Duration Manipulation on Brain-Derived Neurotrophic Factor in Adolescents at Risk for Type 2...

This study examined the effect of sleep duration manipulation on serum brain-derived neurotrophic factor (BDNF) levels in adolescents at risk for type 2 diabetes (T2D). A randomized (1:1), sex-stratified, crossover study design was used to experimentally manipulate sleep duration using actigraphy. Time in bed was increased (IN) and decreased (DE) by 1.5 h per night for 1 week each, with conditions separated by a 1-week washout period of habitual sleep. Sleep manipulations were based on participants' mean baseline sleep duration obtained during 1 week of habitual (HB) sleep. Following each sleep condition, fasted blood samples were collected for the analysis of serum BDNF. Adolescent participants (n = 36, 52.8% female, mean age = 15.1 ± 1.3 years) with severe obesity (> 99th BMI percentile) successfully increased and decreased their sleep duration by +1:02 h/night and -1:19 h/night, respectively, based on a week of HB sleep duration (mean = 7:31 h/night). Increasing sleep duration resulted in a significant (~14%) decrease in serum BDNF compared to the HB and DE weeks, while no significant differences were observed between the HB and DE weeks. This study provides the first experimental evidence that sleep duration influences serum BDNF levels in adolescents at risk for type 2 diabetes. Lower BDNF levels following sleep extension, alongside previously reported improvements in insulin sensitivity, may reflect reduced physiological stress or compensatory neurotrophic signalling, although the underlying mechanisms remain unclear. In contrast, higher BDNF levels during habitual and restricted sleep likely reflect adaptive responses to insufficient sleep rather than improved metabolic function. Trial Registration: ClinicalTrials.gov identifier: NCT03754036.