This randomized crossover study investigated the effect of sleep duration manipulation on serum brain-derived neurotrophic factor (BDNF) levels in adolescents at risk for type 2 diabetes (T2D). Conducted by Dutil et al., the research involved a sample of 36 adolescents, with a mean age of 15.1 years, who were categorized as severely obese (greater than the 99th BMI percentile).
The study employed a sex-stratified design where participants underwent two sleep manipulation conditions: an increase in sleep duration (IN) and a decrease in sleep duration (DE), each lasting one week, separated by a one-week washout period of habitual sleep. The manipulation aimed to adjust sleep duration by 1.5 hours per night based on the participants’ baseline sleep duration, which averaged 7 hours and 31 minutes per night.
Following each condition, participants provided fasted blood samples for BDNF analysis. The results indicated that increasing sleep duration led to a significant decrease in serum BDNF levels by approximately 14% compared to both the habitual and decreased sleep conditions. Conversely, no significant differences were observed between the habitual and decreased sleep conditions.
This finding suggests that sleep duration can influence serum BDNF levels in adolescents at risk for T2D. The authors speculate that the lower BDNF levels following sleep extension, alongside improvements in insulin sensitivity, may indicate reduced physiological stress or a compensatory neurotrophic signaling response. However, the exact mechanisms behind these changes remain unclear.
Interestingly, the higher BDNF levels observed during habitual and restricted sleep may reflect adaptive responses to insufficient sleep rather than an enhancement of metabolic function.
What this study does not show
This study does not establish a causal relationship between sleep duration and metabolic health outcomes beyond the observed changes in BDNF levels.
Evidence scorecard
- Analytic validity: Established
- Clinical validity: Established
- Clinical utility: Partial
This evidence is based on a randomized controlled trial involving human subjects.