Generally, sleeping pills are prescribed for the treatment of insomnia, but they are not effective in all patients. Poor quality and/or lack of sleep can increase the risk of heart failure, depression, diabetes, and high blood pressure.
All doctors recommend a regular sleep cycle. In other words, going to bed and getting up at the same time every day and, ideally, sleeping eight hours a night. This advice is even more valid with age, since “more than half of people over 65 complain about the quality of their sleep,” said Luis de Lecea, a Stanford University professor and co-author of a study published in the journal Science. In their work, the researchers wanted to understand why sleep quality decreases with age. Therefore, they studied the brain circuits involved in sleep in mice and how they deteriorate with age.
Hypocretins, neurons linked to sleep quality
The researchers were more specifically interested in hypocretin neurons. There are only between 50,000 to 80,000 of these neurons in the human brain. A small amount compared to the billions of others. The scientists opted for a more specific analysis because previous research had already shown that their disruption can cause narcolepsy and a very high need for sleep in certain patients. In other words, hypocretins are linked to sleep quality. Clearly, the more you have, the better you sleep, and vice versa.
Fewer hypocretin neurons as we age
The scientists conducted their experiments with mice of different ages: young, from three to five months, and old, from eighteen to twenty-two months. The goal was to analyze their hypocretins as a function of age and stimulate them to see the effect on the quality of their sleep. To stimulate them, they used light. Results: the rats between 18 and 22 months had lost 38% of their hypocretins compared to young rodents, implying that stimulation and age reduce the number of these neurons.
On the other hand, the researchers also found that the remaining hypocretins in these older mice were more easily activated when stimulated. This could explain the decline in sleep quality: “The neurons become more active and more turned on, and when this is the case you wake up more often,” said Luis de Lecea.
Towards more targeted treatments
According to the authors, by better understanding the neurological mechanisms of sleep, this study could lead to the development of new, more targeted treatments for people suffering from sleeping disorders. In the long term, this study could therefore lead to a major breakthrough, especially since current drugs, especially sleeping pills, “can lead to cognitive difficulties or falls,” says Luis de Lecea.