How does sleep impact heart disease?
Most of us are well aware of how vital adequate sleep is for our overall wellbeing and health. But even so, very few Americans are getting the proper amount of sleep per night. For those of us who aren’t getting enough sleep, time to listen up. Recently, the American Heart Association added sleep to their Life’s Simple 7 recommendations for optimal heart health. Let’s look at the evidence to better understand why they did so - what constitutes poor sleep (it’s not as simple as not getting enough of it!), why poor sleep might increase risk of heart disease, and how to take steps to improve sleep.
What is poor sleep?
Poor sleep is a problem that affects approximately ⅓ of Americans. Regularly getting less than 7 hours of sleep per night will put you in the category of sleep deprived, with the American Heart Association defining adequate sleep as somewhere between 7 and 9 hours of sleep.
Just as important as sleep duration (ie quantity of sleep), is sleep quality - or how well you sleep once you’ve hit the pillow. Poor sleep quality can include things like constant waking, inability to fall asleep for long periods of time, and conditions like sleep apnea. Obstructive sleep apnea (OSA), in particular, is a serious medical condition that has been directly linked to heart related issues including hypertension, atrial fibrillation, and heart failure. Individuals that suffer from OSA experience a 140% greater risk of heart failure and 30% greater risk of heart disease than those without the disorder.
How does poor sleep impact the risk of heart disease?
Epidemiologic studies have shown that inappropriate sleep duration is associated with coronary heart disease. Another study observed the specific effects experienced during daylight savings time. When the clock jumped forward an hour, and therefore an hour of sleep was lost, heart attacks rose by 24%.
Why might this be? Poor sleep is known to impact several risk factors for heart disease. Not getting a sufficient amount of sleep increases levels of cortisol, revs up your sympathetic nervous system, and increases levels of inflammation. Normal, healthy sleep allows your body to rest, and with that decreased blood pressure and heart rate. With constant wake ups or inability to fall asleep, the body remains in its heightened state. Short sleep, shift work, and obstructive sleep apnea have all been found to increase the risk of hypertension. These altered hemodynamics probably play a role in the increased risk of heart disease.
Sufficient sleep also indirectly plays a role in weight management and diet. Those that sleep less than the recommended 7 to 8 hours per night are more likely to have altered glucose homeostasis and experience cravings for salt and refined fats, increasing risk of weight gain and cardiometabolic risk factors like insulin resistance and metabolic syndrome.
Tips to improve sleep for heart health
There are many simple yet effective ways to begin improving the quality of sleep you get each night.
Consistent sleep schedule. Just like many of us do for our kids, we as adults can benefit from creating a routine to trigger the body that it is time for rest. The body adapts quickly, and will begin to catch onto a consistent routine. This means that you will begin to feel tired around the same time each evening with enough repetition. Erratic sleep schedules negatively impact the body and keep it guessing. Create a wind down routine for your body with either a regular bath, herbal tea, journaling, or meditation.
Diet. Pay close attention to your diet, especially in the evening. Alcohol, processed food, and sugar are vital to avoid when nearing the time for sleep. Alcohol elevates your resting heart rate and prevents the body from entering quality REM sleep. REM is vital for learning, brain health, and memory. It also predisposes you to frequent wake ups. While red wine *may* have some heart health benefits in low to moderate quantities (as I discussed here), it is ideal to avoid any type of alcohol within 3 hours of sleep. Alcohol and junk food also cause sleep disruptions by causing conflicting signals and disrupting our natural circadian rhythm.
Caffeine. This stimulant has the ability to stay in the bloodstream for as long as 10 hours. Depending on genetic variations, it may stick around for quite some time and disrupt your sleep. Some people can have caffeine as late as 3 pm (fast metabolizers) with no effect on sleep, while others need to have their last bit before noon or they risk a sleepless night (slow metabolizers). Either way, pay attention to your body and honor it (slow metabolizer here!)
Avoid blue light. Lights that come from items like our phones, TV, and laptops contain blue light, which is known to block the hormone that makes us sleepy, melatonin. During the wind down process, it is best to avoid any device that emits blue light in order to allow the body to begin to prepare for sleep. Ideally shut these things down about an hour before bed, and also dim your regular lights as well.
Exercise during the day. Include vigorous physical activity during the day in order to promote healthy sleep at night. The sedentary lifestyle that most Americans have adopted is not conducive to proper sleep. Not only is physical exercise in and of itself healthy for the heart, expending energy during the day allows us to feel tired, which results in better sleep.
Heart disease and sleep - the skinny
Quality sleep is non-negotiable when it comes to our overall health. Taking the time to implement a consistent, solid sleep routine is one of several lifestyle factors important for optimal heart health. Prioritizing a minimum of 7 hours of sleep per night can make dramatic changes to your wellbeing and as such, you can remain healthy, energized, and rested. If you are consistently having issues going to sleep despite optimizing your sleep hygiene, it may be worth seeing a specialist to rule out medical causes and potentially get a sleep study. Your heart (and rest of your body) will thank you.