More dream sleep linked to lower risk of 83 diseases, including diabetes

• A new large-scale study investigates the associations between sleep duration and disease risk.
• Participants wore wrist accelerometers for 1 week to assess not only their sleep duration, but also how long they spent in different phases of the sleep cycle.
• Among other findings, the researchers showed that more dream sleep was associated with a reduced risk of more than 80 health conditions.
• Overall, people who slept for 6–8 hours had the lowest risk of health issues.

A new study, published in PLOS Medicine, analyzed real-world data from almost 100,000 participants in the UK Biobank databank.

They found that greater rapid-eye movement (REM, or dream) sleep was associated with a lower risk of 83 diseases, while more deep sleep was associated with a lower risk of seven health conditions.

Although previous studies have linked short sleep duration with disease and an increased risk of mortality, they often relied upon self-reported sleep duration. In other words, participants simply told them how long they had slept for.

This is not ideal. People can misremember, and we are not always aware of when we actually drop off or wake up during the night.

Also, self-reported sleep duration provides no information about time spent in sleep stages, such as deep sleep and REM sleep.

In the current study, scientists used wrist-worn accelerometers to gather much more detailed information about participants’ sleep stages, plus how long they slept for and how irregular their sleep patterns were.