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). Conducted as a randomized crossover study, the research involved 36 adolescent participants, with a mean age of 15.1 years and a majority being female (52.8%). The participants were selected based on their severe obesity status, defined as being above the 99th BMI percentile.
The study utilized actigraphy to manipulate sleep duration, increasing and decreasing the time in bed by 1.5 hours per night for one week each, with a one-week washout period of habitual sleep in between. The baseline sleep duration was determined from a week of habitual sleep, which averaged 7 hours and 31 minutes per night.
Following each sleep condition, fasted blood samples were collected to analyze serum BDNF levels. The results indicated that increasing sleep duration led to a significant decrease in serum BDNF levels by approximately 14% compared to both the habitual sleep and decreased sleep weeks. Conversely, no significant differences were observed between the habitual and decreased sleep conditions.
This study provides the first experimental evidence suggesting that sleep duration can influence serum BDNF levels in adolescents at risk for T2D. The findings indicate that lower BDNF levels following sleep extension, along with previously reported improvements in insulin sensitivity, may suggest a reduction in physiological stress or compensatory neurotrophic signaling. However, the underlying mechanisms for these changes remain unclear.
In contrast, the higher BDNF levels observed during habitual and restricted sleep conditions likely reflect adaptive responses to insufficient sleep rather than an improvement in metabolic function. This highlights the complex relationship between sleep, metabolic health, and neurotrophic factors in adolescents.
What this study does not show
This study does not establish a direct causal relationship between sleep duration manipulation and improved metabolic health outcomes in adolescents.
Evidence scorecard
- Analytic validity: Established
- Clinical validity: Established
- Clinical utility: Partial
The evidence class is human_rct, indicating a randomized controlled trial with direct implications for human health.