Scientists discover how deep sleep builds muscle, burns fat, and boosts the brain
Scientists have discovered a surprising two-way relationship between sleep and growth hormone, revealing how the brain carefully balances physical recovery with wakefulness. The findings could help explain why poor sleep harms metabolism and brain health, potentially opening the door to new treatments for sleep and neurological disorders.
Key points
- UC Berkeley researchers identified brain neurons that control growth hormone release during sleep in mice.
- Growth hormone also signals back to the brain to influence wakefulness, forming a feedback loop.
- The findings could aid future treatments for sleep disorders tied to metabolic and neurological disease.
Researchers at the University of California, Berkeley, have mapped the brain circuitry that links deep sleep to growth hormone release, according to a study published in the journal Cell. The team identified neurons in the hypothalamus that regulate the hormone during sleep and found a previously unknown feedback system balancing hormone levels and wakefulness.
The work was conducted in the laboratory of Yang Dan, a professor of neuroscience and of molecular and cell biology at UC Berkeley. The experiments were done in mice, and the article states that further research is needed to determine how these mechanisms operate in humans.
How the circuit works
The researchers focused on the hypothalamus and on neurons producing growth hormone-releasing hormone (GHRH) and two types of somatostatin-producing neurons. GHRH encourages growth hormone secretion while somatostatin suppresses it.
During REM sleep, activity involving both GHRH and somatostatin increases, contributing to growth hormone release. During non-REM sleep, somatostatin activity falls while GHRH activity rises moderately, also promoting secretion. Growth hormone then stimulates the locus coeruleus, a brainstem region involved in alertness, helping drive the transition toward waking.
Sleep drives growth hormone release, and growth hormone feeds back to regulate wakefulness, and this balance is essential for growth, repair and metabolic health.
— Daniel Silverman
Possible future treatments
The article says the findings could eventually help scientists develop approaches to treating sleep disorders linked to metabolic diseases such as diabetes, and neurological conditions including Parkinson's and Alzheimer's. The researchers recorded neural activity in mice using implanted electrodes and light stimulation of specific neurons.
The research was supported by the Howard Hughes Medical Institute and the Pivotal Life Sciences Chancellor's Chair fund.
