Sustained polyphasic sleep restriction abolishes human growth hormone release

Area of Science:

• Neuroscience
• Endocrinology
• Sleep Medicine

Background:

• Voluntary sleep restriction is prevalent in industrialized societies, often driven by a desire for increased productivity.
• This study investigated the effects of a radically polyphasic sleep schedule on neural, cognitive, and endocrine functions.

Observation:

• Ten healthy young participants attempted a polyphasic sleep schedule, napping 20 minutes every 4 hours, totaling 2 hours of sleep daily.
• All but one participant discontinued the schedule within a month; the remaining participant adhered for five weeks.
• Cognitive and psychiatric measures showed minor changes, while cortisol and melatonin levels remained largely unaffected.

Findings:

• Growth hormone release was significantly reduced by over 95% and altered in pattern during polyphasic sleep.
• The radical polyphasic sleep schedule was poorly tolerated, even by highly motivated individuals.
• Observed decreases in vigilance and neurophysiological sleep changes raise concerns about the schedule's feasibility.

Implications:

• Radically polyphasic sleep may not adequately fulfill the essential functions of sleep.
• The findings question the long-term viability and health impacts of extreme sleep scheduling.
• Further research is needed to understand the neuroendocrine and cognitive consequences of severe sleep restriction.