AHA Statement Zeroes In On Sleep Health

Researchers shouldn’t snooze on incorporating sleep health elements into population studies as a way to better understand how factors beyond sleep disorders and hours per night impact CVD risk, says the American Heart Association (AHA).

In 2022, the AHA added sleep duration to its Life’s Simple 7 metric, which then became Life’s Essential 8, highlighting sleep’s importance in cardiovascular health and role as an emerging target for preventive efforts. Poor sleep quality and duration—lasting both less than 7 hours and more than 9 hours—have been shown to be associated with cardiometabolic syndrome as well as increased risk of hypertension, CVD events, obesity, and diabetes.

The new scientific statement published online this week ahead of print in Circulation: Cardiovascular Quality and Outcomes delves into several other lesser known and less studied components of sleep health. These include quality, continuity, timing, satisfaction, regularity, sleep-related daytime function, and architecture.

“All of these concepts are important to consider when we're talking about sleep and its relation to cardiovascular health,” writing chair Marie-Pierre St-Onge, PhD (Columbia University Irving Medical Center, New York, NY), told TCTMD.

“We have a lot of information about sleep duration, and we can make these recommendations related to [it] because the research is there,” she said. “But if we don't bring attention to these other aspects of sleep, then they're not measured, and if they're not measured, they're not being considered and we can't make recommendations related to those.”

As a whole, these less-studied components contribute to cardiometabolic health and related risk factors, though measuring and documenting sleep health aren’t simple tasks, the writing committee notes. Methods typically involve self-reports, although some objective tools like polysomnography and sensors are useful in certain situations, they say.

Multidisciplinary Exploration Needed

To better understand the connections between all the components of sleep health and CVD as well as find actionable interventions, St-Onge and colleagues recommend that researchers from multiple disciplines—including but not restricted to sleep, cardiology, endocrinology, gastroenterology, nephrology, and hepatology—implement the recommended tools and definitions in the scientific statement when they plan out studies. 

Among the unknowns that the committee feels need clarification are immunologic responses, behavioral and cognitive health, emotional well-being, and cardiovascular fitness in relation to sleep health. They also recommend examining “joint or additive effects across sleep dimensions to identify which specific combinations confer greatest risk (eg, insomnia complaints with short sleep duration, delayed timing with sleep irregularity).”

Physiologic studies could help provide more robust evidence on how specific-sleep architecture metrics like rapid-eye movement (REM) and non-rapid-eye movement (NREM) cycles elevate CV risk beyond other sleep dimensions, the statement advises.

“We also call for clinical studies to test causation through interventions to improve sleep health as a means of enhancing [cardiometabolic health] as well as for basic research to evaluate mechanisms through appropriate animal models,” they add.

If you're only asking about sleep duration and someone says they usually get 8 hours per night, you may miss the fact that . . . it takes them an hour to fall asleep. Marie-Pierre St-Onge

To TCTMD, St-Onge noted that “every little bit helps” when it comes to widening the net of sleep research, with many of the recommended measures being relatively simple to implement and involving little effort for trialists.

The committee also recognizes that “sleep health is not equitable.” They note that recent data from several studies like the Multi-Ethnic Study of Atherosclerosis (MESA) show consistent associations between lower socioeconomic status and suboptimal sleep health, including shorter duration and more irregular patterns.

There also is evidence to support a higher burden of undiagnosed sleep disorders in people from underrepresented racial or ethnic groups, with MESA data showing that Black adults have the greatest global sleep health disparity of all groups.

Talking to patients about sleep is the other component that the committee believes can help elevate the importance of sleep health for individuals and improve assessment beyond the standard clinical history.

“If you're only asking about sleep duration and someone says they usually get 8 hours per night, you may miss the fact that to get that they're actually spending 10 hours in bed and it takes them an hour to fall asleep,” St-Onge said. “They may be up for an hour in the middle of the night, or they're awake earlier than they would like to be, and they're not happy when they wake up because they didn’t get the sleep they needed [despite] the amount of time they spent in bed.”

Finally, she noted that things are moving in the right direction when it comes to understanding how components of sleep health play into cardiometabolic health, but more data are needed.

“I think the field is definitely growing [and] scientists are tapping into these new dimensions of sleep and trying to understand these patterns and how they're associated with chronic diseases,” St-Onge said.