If you’ve ever cared for small children, worked a night shift, or stayed out late at a party, you know the feeling of going to bed much later than usual and sleeping in the next day. Sleep researchers call this phenomenon “social jet lag.” They have found it can lead to many negative consequences, including poor sleep quality, reduced cognitive performance, unhealthy eating patterns, depression, and anxiety.
Last month, a large new study looked at the link between social jet lag and heart disease. Researchers from Vanderbilt University Medical Center tracked the sleep patterns of more than 2,000 adults aged 45 and older over the course of a week and then scanned the participants’ hearts.
The study found people with more irregular sleeping patterns—those whose sleep duration varied by more than two hours a night—were significantly more likely to have atherosclerosis, a build-up of plaque in their arteries that can lead to heart attack, stroke, and blood clots.
That is, people who slept for vastly different periods during the week—such as sleeping only six hours on Thursday night, then 10 hours on Friday night—had much higher risks of developing heart disease. This held true when researchers factored out other risk factors of heart disease such as sleep apnea, consistently getting too little sleep, body mass index, high cholesterol, and diabetes.
It’s important to note: this type of study doesn’t prove that irregular sleep patterns cause heart disease. But it does provide another piece of evidence that demonstrates a consistent sleep schedule is an important component of overall health.
Doctors don’t understand why consistent sleep promotes cardiovascular health. One theory is that your circadian rhythm—your body’s internal, 24-hour clock—helps to regulate heart function. At night, your heart rate and blood pressure change depending on what phase of sleep you’re in. During non-rapid eye movement (REM) sleep, they drop and hold steady; during REM sleep, when you tend to have vivid dreams, heart rate and blood pressure rise and are more varied. Moving through these patterns consistently may be important for heart health.
Sleep experts recommend good sleep hygiene to help maintain a consistent sleep schedule. This includes:
- Cutting down on evening screen time. Televisions, computers and phones emit blue light, which affects the circadian rhythm. Avoid using these types of devices one hour before bed.
- Engaging in physical activity. Regular exercise can help you feel more tired. If you’re exercising outside, the exposure to natural light helps to regulate your circadian rhythm. Avoid exercising two hours before bed to give your body time to wind down.
- Following a bedtime routine. Repeating the same steps each night will give your body cues that it’s time to go to sleep.
- Avoiding long naps. Long naps can disrupt nighttime sleep. Try not to nap for more than 30 minutes and no later than early afternoon.
- Reducing alcohol and caffeine use. Although alcohol can make you feel sleepy, it leads to poor quality sleep. Caffeine can linger in your system, making it difficult to fall asleep.
The take-home message: A new study provides evidence that a consistent sleep schedule is linked to cardiovascular health.
