sleep tagged posts

On Earth, most of us rarely have to think about the signals that keep our internal clocks aligned. The sun rises, daylight changes, darkness arrives and morning comes again.

Our bodies have evolved alongside this roughly 24-hour cycle. Light is one of the strongest signals our bodies use to synchronize the circadian clock. But what happens when the sun no longer provides a reliable schedule?

A spacecraft orbits Earth roughly every 90 minutes, so astronauts experience about 16 sunrises and sunsets every 24 hours. They cannot go to sleep every time the sun disappears—but their bodies still need to know when it is time to sleep, wake, eat, exercise and work.

This makes spaceflight more than just an engineering cha...

The familiar labels “night owl” and “early bird,” long used in sleep research, don’t fully capture the diversity of human internal clocks, a new study has found. The McGill University-led study published in Nature Communications found the two sleep-wake patterns, called chronotypes, contain a total of five distinct biological subtypes, each associated with different patterns of behavior and health.

A chronotype is based on the parts of a 24-hour period when a person naturally feels most alert or ready to sleep. Previous research has linked late chronotypes to worse health outcomes, but results have often been inconsistent. The new findings help explain why, the authors said.

“Rather than asking whether night owls are more at risk, the better question may be...

While everyone knows that a good night’s sleep restores energy, a new Cornell University study finds it resets another vital function: memory.

Learning or experiencing new things activates neurons in the hippocampus, a region of the brain vital for memory. Later, while we sleep, those same neurons repeat the same pattern of activity, which is how the brain consolidates those memories that are then stored in a large area called the cortex. But how is it that we can keep learning new things for a lifetime without using up all of our neurons?

A study, “A Hippocampal Circuit Mechanism to Balance Memory Reactivation During Sleep,” published in Science, finds at certain times during deep sleep, certain parts of the hippocampus go silent, allowing those...

Simulated effects of microgravity significantly affect rhythmicity and sleep in humans, a new study from the University of Surrey finds. Such disturbances could negatively affect the physiology and performance of astronauts in space.

Previous findings have shown that astronauts exposed to microgravity, simulated via 60 days of constant bed rest at a six-degree head-down tilt angle, experience changes to physiology, including immune suppression, increased inflammation, and reduced muscle mass and bone density. However, a less-studied aspect of physiology concerning the effects of microgravity is sleep and biological rhythms.

Lead author Dr María-Ángeles Bonmatí-Carrión, a post-doctoral researcher at the University of Surrey (currently at CIBERFES (Carlos III Health Institute), Un...