A reexamination of the relationship between growth hormone secretion and slow wave sleep using delta wave analysis.

Sleep onset growth hormone secretion is a reliable and reproducible finding in young adults and children. Secretion typically occurs during the first non-REM period of sleep and, despite some evidence to the contrary, growth hormone secretion has frequently been associated with the first period of slow wave sleep. By measuring delta wave activity (0.5-2 Hz) instead of slow wave sleep and, accounting for the within subject variability, it has not been possible to demonstrate a consistent or statistically significant linear relationship between delta wave activity and sleep-related growth hormone secretion. This suggests the presence of more complex mediating factors and the possibility that sleep onset and growth hormone secretion are two separate processes which are independently stimulated by events associated with sleep onset.