Influence of sleep deprivation on plasma ghrelin levels in healthy subjects

Plasma ghrelin levels increase between meals and during the night, but the influence of sleep or sleep deprivation is unknown.

In ten healthy male volunteers changes in ghrelin levels were measured during 24 hours. In a cross-over study subjects were allowed to sleep between 2300 and 0700 hours or kept awake.

Ghrelin plasma levels showed the established relationship to meals, i.e. levels increased prior to every meal and sharply declined thereafter. During sleep ghrelin levels displayed an initial increase followed by a decline towards morning awakening. In contrast, during the sleep deprivation condition ghrelin levels increased steadily to a plateau and did not decrease prior to breakfast again.

We conclude that an early increase of ghrelin levels during sleep and a decline in the morning hours are related to sleep itself, because overnight wakefulness coincides with steadily increasing ghrelin levels.