Are you going to bed at 2 A.M. one night and 10 P.M. the next?
Reviewed by Dietitian Casey Wing, RD, CD
Key Points
- Irregular sleep disrupts circadian rhythms, raising stress hormones and straining heart health.
- Sleep schedule variability is linked to higher blood pressure, inflammation and heart disease risk.
- Consistent sleep supports heart health by aiding metabolism, blood pressure dips and healthy habits.
Find yourself going to bed at 11 P.M. one night, then 1 A.M. the next? Perhaps you’re bingeing a new show, finishing up work or just trying to get some alone time? While inconsistent sleep schedules are common, cardiologists warn this sleep habit might be harming your heart.
When you don’t get proper sleep, your body misses out on the important recovery time it needs each night, says Douglas Zuckermann, M.D.a board-certified cardiologist. “This leads to higher stress hormones like cortisol, increased blood pressure while you sleep and more inflammation—all things that put extra pressure on your heart and blood vessels. If this keeps happening, it makes your heart work harder and raises your risk for developing issues like high blood pressure and heart disease.”
Ahead, cardiologists further explain how an inconsistent sleep schedule affects your heart health.
How An Inconsistent Sleep Schedule Affects Your Heart Health
Disrupts the Circadian Rhythm
Nearly every organ within our body follows a circadian rhythm—an internal 24-hour clock that regulates everyday functions like body temperature, hormone release and sleep. Circadian health refers to how well your body’s internal clock system is functioning and aligned with the natural day-night cycle. For example, it determines whether you feel sleepy at night and alert in the morning, and whether digestion follows daily patterns.
However, these rhythms can easily become thrown off by various factors such as late-night light exposure, traveling across time zones or caring for a little one in the middle of the night. When circadian rhythms become misaligned, it can negatively affect your heart.
“An inconsistent sleep schedule throws off your body’s master clock, or circadian rhythm, which regulates vital functions like your heart rate and blood pressure,” explains Cynthia A. Kos, DO, FACCa board-certified cardiologist. “This disruption can lead to heightened sympathetic nervous system activity, keeping your body in a ‘fight or flight’ state, which increases stress on your heart over time.”
Kos points to a study that found individuals with the most irregular sleep schedules had nearly double the risk of developing cardiovascular disease over a 5-year period compared to those with a more regular sleep pattern. “This suggests that even a 60-minute day-to-day variation in your sleep schedule could have a long-term impact on your heart,” she adds.
Prevents Normal Blood Pressure Dipping at Night
Your blood pressure follows a circadian rhythm, too—typically highest in the morning and lowest while you are sleeping. Research has found that sleep irregularity is associated with elevated blood pressure.
Kos explains the reasoning behind this: “When your sleep schedule is erratic, it can prevent your blood pressure from dipping at night as it naturally should, leading to higher average blood pressure levels. This constant pressure can strain your arteries and increase your risk for heart disease.”
“Blood pressure ‘dips’—the natural drop in blood pressure during sleep—at night are part of the body’s natural circadian rhythm, and patients who do not have dips are at increased cardiovascular risk,” agrees Caroline Ball, M.D., FACCa board-certified cardiologist.
Interferes with Metabolism
Following an irregular sleep schedule disrupts daily habits, including when and what you eat. Plus, on days where they don’t get enough sleep, people are more likely to reach for high-calorie beverages or treats to perk up, science confirms.
“Poor sleep can affect your adherence to heart healthy habits, as well—it’s harder to make good food choices and exercise regularly when you are tired,” explains Ball. Studies have linked greater variability in sleep schedules with lower adherence to healthy behaviors.
“Irregular sleep can interfere with your body’s metabolism, affecting how it processes sugar and regulates appetite,” adds Kos. Studies show that lower sleep regularity is associated with elevated blood pressure, higher blood sugar, metabolic syndrome and a higher BMI (body mass index)—all of which can increase risk for heart disease.
Research has linked “social jetlag,” the shift in sleep schedule between workdays and free days, to a higher risk of being overweight. Over time, these metabolic disturbances contribute to an environment that is unhealthy for your heart, says Kos.
Promotes Inflammation
While some inflammation is necessary, too much can cause harm. “Studies have shown that irregular sleep can promote chronic inflammation, a key factor in the development of atherosclerosis, which is the buildup of plaque in the arteries,” says Kos. Research suggests that greater inconsistency in sleep duration and timing is associated with a higher burden of atherosclerosis, she adds.
Interestingly, both insufficient and excessive sleep are linked to inflammation. Zuckermann explains: “Sleep deprivation disrupts the body’s hormonal balance, increases inflammation and impairs glucose metabolism, all of which can strain the cardiovascular system and contribute to disease development.” On the other hand, sleeping too long can also disrupt metabolic processes and circadian rhythms, potentially leading to worsened blood glucose regulation, higher blood pressure and increased inflammation—again, all of which can contribute to heart disease, he adds.
How to Get on A More Consistent Sleep Schedule
Cardiologists share their top tips for how to get a better night’s sleep through a more consistent bedtime schedule:
- Maintain a consistent sleep schedule. Stick to a sleep schedule that you can consistently achieve each night and make sure you follow the same schedule, even on the weekends.
- Set a bedtime alarm. You likely set a daily alarm to wake up; why not set one to remind you to go to bed?
- Get regular daytime exercise. Engage in regular daytime exercise to support your heart health and help lull you to better sleep.
- Avoid coffee late in the day. Set a caffeine cutoff time—you may continue to feel its effects for up to 6 hours after consumption, though this can vary greatly for each individual. Know your personal cutoff time to prevent sleep disruptions.
- Limit the booze. “While alcohol may initially make you feel sleepy, it can disrupt sleep patterns and lead to more fragmented sleep, ultimately increasing stress on the heart,” says Zuckermann. Try to limit alcohol intake for better heart health and sleep.
- Turn off screens. Screen exposure before bedtime emits blue light, which suppresses melatonin production and interferes with your body’s ability to fall asleep and stay asleep, says Zuckermann. Put away computers, tablets and phones, and turn off the TV at least 30 minutes before bed.
- Create a sleep-friendly bedroom. Make sure your bedroom is cool, dark and quiet to create an environment that supports uninterrupted sleep, says Kos.
Our Expert Take
There are many factors that impact heart health, and sleep is one of them. Cardiologists warn that having an inconsistent sleeping schedule, such as going to bed at 2 A.M. one night and 11 P.M. the next, may be harming your heart. They explain that this habit disrupts your natural circadian rhythm, prevents normal blood pressure dips, interferes with metabolism and promotes inflammation—all of which can negatively impact heart health. Cardiologists stress the importance of creating an environment more conducive to consistent sleep to help prevent these risk factors. Better sleep can result in a healthier heart.
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