The sleep hormone melatonin could be crucial for people as they get older because of the role sleep and the body’s daily rhythm play in brain health.

Certain diseases and natural aging affect that circadian rhythm or are linked to disruptions in it, but melatonin, in its role of regulating our internal clocks, could have benefits for those conditions, according to a new review in the British Journal of Pharmacology. The hormone has been shown to improve sleep disorders such as insomnia and jet lag, sleep quality and the neurodegenerative Alzheimer’s disease. The review explores the relationship between melatonin and health, as it is connected to aging.

“With age and certain diseases the robustness of the circadian system decreases and melatonin production is diminished or shifted,” according to the review.

And that could be hazardous to health in many different ways.

“Deviant circadian rhythms and poor sleep quality are associated with increased risks of cardiovascular, metabolic and cognitive diseases, as well poor quality of life and increased risks of premature death,” researcher Dr. Nava Zisapel, of Israel’s Tel Aviv University, said in a statement from journal publisher Wiley.

We still don’t fully understand sleep, and we certainly don’t have a complete understanding of the human brain. But previous research suggests melatonin supplements help realign a person’s circadian rhythm and sleep, and can improve cardiovascular and cognitive health, including in patients with Alzheimer’s disease, who may start producing less melatonin in the early stages of their illness.

Research has also shown that sleep, while crucial for biological function in general, is important for cognitive function in the elderly — including one study that found a one-hour nap in the middle of the day could be key for seniors.

Melatonin “represents a promising investigational route for early intervention to promote healthy physical and mental aging,” the review authors wrote.