Staying up late may be harmful to your heart health — particularly if you’re a woman.
“Sleep is a modifiable cardiovascular risk factor. It’s not as strong as smoking, but it’s far from trivial,” says Matthew J. Sousa, MD, an interventional cardiologist with Norton Heart & Vascular Institute in Louisville, Kentucky, who was not involved in the research.
‘Evening People’ Faced Higher Odds of Heart Attack and Stroke
For the study, researchers used health data from the UK Biobank looking at more than 300,000 adults in the United Kingdom with an average age of 57.
Among the participants, 8 percent classified themselves as “definitely evening people” with a late-night bedtime, 24 percent self-reported as “definitely morning people” with an earlier bedtime, and 67 percent were “intermediate,” meaning they were either unsure of their status or were neither a morning nor an evening person.
The researchers made the following observations when comparing evening or morning people with those who had “intermediate” sleep timing habits:
- Evening people were 79 percent more likely to have a poor overall heart health score over the 14 years of follow-up.
- Evening people had a 16 percent higher risk of having a heart attack or stroke over the 14 years.
- Morning people had a 5 percent lower prevalence of low heart health scores.
The link between night owl preferences and poor heart health was more pronounced in women than in men, which Dr. Sousa suggests may be the result of a combination of factors — including underdiagnosed and undertreated sleep disorders, biological differences, chronic stress, and differences in types of heart disease.
Why Do Late Bedtimes Connect to Poorer Heart Health?
“What’s often surprising to the public, but not to cardiologists, is that sleep isn’t just ‘rest’ — it’s a major regulator of blood pressure,” Sousa says. “Poor sleep has been known to correlate with worse heart outcomes, which is very consistent with existing physiology.”
Lead study author Sina Kianersi, PhD, a postdoctoral research fellow at Brigham and Women’s Hospital and Harvard Medical School in Boston, points out that late bedtimes can throw off a person’s “body clock,” or circadian rhythms.
“A likely explanation involves circadian misalignment, which is when the body’s internal clock is out of sync with real-life schedules such as work, sleep timing, meals, and light exposure,” he says.
It’s important to note that the study was observational, so it doesn’t prove that later sleep-wake time preferences cause poor heart health, but only that there’s a connection.
“That’s also where we have to be careful: Association is not the same as causation, and poor sleep is tightly linked to stress, shift work, depression, anxiety, pain, caregiving burden, and socioeconomic factors,” Sousa says, all of which might result in heart problems.
Dr. Kianersi also notes that night owls tend to have other habits that negatively affect their overall health, including higher rates of nicotine use and inadequate sleep.
The UK Biobank population is considered to be significantly healthier than the general population, so results may not be fully applicable to broader groups. In addition, participant responses were self-reported, which can introduce errors.
Better Sleep Patterns May Improve Heart Health for Night Owls
The study results suggest that night owls can take action to improve their heart health by modifying their sleep patterns.
“For people who lean later, the goal is not necessarily to become an early bird, but to build a schedule that is sustainable and consistent, and to support it with healthy routines during waking hours,” Kianersi says.
- Try for seven to nine hours of quality sleep per night, though some adults may do well at 6.5 to 7.5 hours.
- Keep bedtime and wake time consistent, including on weekends if possible.
- Get plenty of natural light throughout the day, and avoid artificial light in the evening
- Avoid caffeine and any kind of food or beverage within several hours of bedtime.
- Make your bedroom a sanctum by keeping it cool, dark, and quiet.
- Get screened if you’re chronically tired, snore loudly, or have uncontrolled high blood pressure; you may have sleep apnea.
Remember that some progress is better than none. “Improvements often come from small, consistent changes rather than perfect sleep,” Sousa says.