Short sleep and ghrelin: a meta-analysis of 21 studies

A systematic review and meta-analysis published in Obesity Reviews (2020) and indexed in PubMed: 21 studies, 2,250 participants. Ghrelin levels were higher in the short sleep group (SMD = 0.14, p = 0.01), a statistically significant and small effect.

The value of the meta-analysis

Pooling 21 different studies with 2,250 participants reduces the weight of the limits of any single study, without removing them: the analysis combines experimental and observational studies that differ from one another. The authors conclude that short sleep duration is associated with higher ghrelin.

In the sleep deprivation studies, the meta-analysis observed higher levels of both ghrelin (SMD = 0.18) and leptin (SMD = 0.24), the satiety hormone: the picture does not all point the same way.

The meta-analysis describes associations between sleep duration and hormones: it does not measure how much weight short sleep adds.

Obesity and sleep: a link still to be understood

Short sleep and obesity are often studied together. This meta-analysis points to a possible hormonal mechanism, not to proof that one causes the other.

The Digital Twin and this research

The Digital Twin lines up the data your devices write to your phone, such as steps, heart rate and sleep, and shows you how they change over time. It does not measure hormones, it does not calculate risk profiles and it does not diagnose: this research describes groups of people, not you. These are data to read together with your doctor.