“Early risers” use CPAP machines longer, giving them greater health benefits

Most people with obstructive sleep apnea — a condition in which normal breathing is regularly interrupted during sleep — are prescribed continuous positive airway pressure, or CPAP, as a treatment. Yet many people don’t use their devices as often or for as long as recommended, reducing their effectiveness.

A new study from Yale reveals that a person’s biological clock can affect their adherence to appropriate CPAP use. Specifically, “morning people,” or those who prefer to wake up earlier, were more likely than others to use their devices for longer periods of time while sleeping, the researchers found. This revelation, they say, could help physicians anticipate adherence issues and proactively manage them.

The study was published on March 14 in the Annals of the American Thoracic Society.

Obstructive sleep apnea is common and affects one in seven people worldwide. When sufferers fall asleep, the muscles in their throat relax and close their airways, interrupting normal breathing.

“As a result, oxygen cannot reach the rest of the body, the brain in particular,” said Andrey Zinchuk, assistant professor of pulmonary, critical care, and sleep medicine at Yale School of Medicine and lead author. of the study. “So before they suffocate, their brain wakes them up. And that can happen anywhere from 10 to 15 times per hour up to 100 times per hour for some people.”

This repeated interruption of sleep has immediate effects; heart rate and blood pressure increase and the body releases stress hormones like cortisol. Untreated, sleep apnea is also associated with long-term health effects, such as high blood pressure, diabetes, stroke, neurocognitive dysfunction, and an increased risk of being involved in accidents. car due to fatigue.

CPAP devices prevent the airways from closing by splinting them open with compressed air. To be fully effective, Zinchuk said, the devices must be worn all night, every night.

“But a lot of people really struggle with it,” he said. “After one year, about half of patients will stop using their device.”

There are a few behavioral and social factors associated with CPAP use, including willingness to change, resilience, socioeconomic status, and social support. But none of the factors studied so far can fully explain why a patient is more or less likely to use their device as instructed.

For the new study, Zinchuk and colleagues examined whether chronotype — or inclination to sleep at a certain time — might contribute to CPAP adherence, using data from the Apnea Positive Pressure Long-term Study. Efficacy Study, a long-term study of the effects of CPAP devices on the health of people with obstructive sleep apnea.

There are three types of chronotypes: morning chronotypes, or what would be colloquially called “early risers”, evening chronotypes or “night owls”, and those somewhere in between, called chronotypes “intermediaries”.

The chronotype classification corresponds to a person’s biological clock. It is assessed by responses to a questionnaire that asks when someone prefers to wake up and go to bed, what time of day they get tired, and what time of day they feel their best performance, among other questions. .

In a sample of 469 CPAP users, researchers found that most had morning (44%) or intermediate (47%) chronotypes and few (8%) had evening chronotypes. Because there were so few participants with an evening chronotype, the researchers compared CPAP use among those with a morning and intermediate chronotype.

They found that over a six-month period, people with a morning chronotype used their CPAP devices more than 40 minutes longer each night, on average, than those with an intermediate chronotype.

“Every additional half hour of CPAP use is clinically meaningful,” Zinchuk said. “It impacts a patient’s quality of life. So 40 minutes is important.”

Zinchuk says more research is needed to determine what factors underlie this relationship between chronotype and CPAP adherence.

“It may be that a person’s biological clock affects the type of sleep apnea they have,” he said. “Some types are more easily treated with CPAP, others with non-CPAP treatments. Or it could just be that people with the morning chronotype are simply better suited to the 9-to-5 lifestyles accepted in our society. ”

Either way, chronotype can be a helpful consideration when treating people with sleep apnea, Zinchuk said.

“For now, the results suggest that the chronotype might be something we should pay more attention to. If a patient is not a morning person, we may be looking more closely at their barriers to using CPAP,” he said. “This study also reiterates how important and influential our biological clocks are for all sorts of health factors, both biological and behavioral.”