World Heart Day 29th September 2016
We all know how great a good night’s rest feels. We wake up feeling refreshed, energized and ready for the day. Unfortunately, this rested feeling is the exception and not the norm for many who live busy lives in the modern society, and the lack of restorative sleep is detrimental not only to our energy levels, but also to our hearts.
According to a published 2015 study1, the average self-reported sleep duration has decreased from over 8 hours in the 1960’s to less than 6.5 hours in 2012, with 20–30% of middle aged Americans reporting sleep duration of less than 6 hours.
Although it may feel like it, sleep cannot be considered as a waste of time. Sleep is an important activity to promote alertness, recharge energy to perform daily activities and a must for our overall health and well-being. And according to numerous studies, it’s essential for a healthy heart.
The human heart is the hero of organs: it pumps blood throughout the body via the circulatory system, supplying oxygen and nutrients to the tissues and removing carbon dioxide and other wastes. If the heart is the good guy, then the bad guys most of us know refer to “French fries”, “smoking”, “stress”, “lack of exercise” among many others. However, a recent study2 published in the journal of Hypertension shows that there is a newly discovered villain: restricted and disrupted sleep.
According to the study, the heart – just like the brain – needs stable and restorative sleep every night in order to rejuvenate properly. Hence, people who repeatedly do not get enough sleep and or have varied sleeping patterns could be increasing their risk of cardiovascular disease.
A 2011 European Heart Journal review3 of 15 medical studies involving almost 475,000 people found that short sleepers had a 48% increased risk of developing or dying from coronary heart disease (CHD) in a seven to 25-year follow-up period (depending on the study) and a 15% greater risk of developing or dying from stroke during this same time. Interestingly, long sleepers — those who averaged nine or more hours a night — also showed a 38% increased risk of developing or dying from CHD and a 65% increased risk of stroke.
An earlier study4 from December 2008 in the Journal of the American Medical Association found that compared with people who sleep seven to nine hours a night, people who don’t get enough shuteye are more likely to develop calcium deposits in their coronary arteries, raising their risk for heart disease. In fact, even after accounting for various other causes, researchers found that when sleep-deprived subjects get just one more hour of sleep per night, they had a 33 percent decrease in their odds of developing calcium deposits in their arteries. Although they’re not certain why sleep helps keep arteries healthy, researchers hypothesize it helps combat stress, and the fact that when you sleep your blood pressure naturally lowers.
For those who already are at risk of heart disease, cardiovascular disease symptoms can sometimes be a cause of poor sleep. According to Dr. Wong Teck Wee, Consultant Interventional Cardiologist at iHeal Medical Centre, conditions that may disrupt your sleep include: chest pain, arrhythmias (abnormal heart rhythms, such as atrial fibrillation), sleep apnea (a series of pathological breathing pauses during sleep that stress your body), and fluid buildup in the lungs due to heart failure. Furthermore, patients with ischaemic heart disease (disease characterized by reduced blood supply to the heart) usually report comorbid insomnia. This in turn could become an exhausting, vicious cycle of inadequate sleep contributing to cardiovascular disease versus cardiovascular disease disturbing your sleep.
Dr Wong also reiterated that poor sleep has been linked to hypertension, atherosclerosis (clogging or hardening of the arteries that is associated with ischaemic heart disease), heart failure, stroke, diabetes and obesity. Most researchers believe that insomnia is linked to cardiovascular health in two possible ways: (1) directly, via physical changes and (2) indirectly, via behavioral factors. First, physical changes include hypertension, appetite, inflammation, and other bodily stress reactions. Poor sleep increases inflammatory substances in your body, such as C-reactive protein and stress hormones (cortisol). Inflammation, the body’s protective response to injury, infection or disease, may be part of the reason poor sleep affects your cardiovascular system. Secondly, common behavioral factors of poor sleep are low mood, low motivation, and cognitive difficulties that can negatively impact decision-making about healthy behaviors.
Another condition that can affect heart health is sleep apnea, a condition that causes people to wake up frequently throughout the night. This disrupted sleep can lead to higher blood pressure at night and during the day, and may increase the risk for heart attacks and stroke. A study5 by the National Sleep Foundation found that over an eight-year period, men with severe sleep apnea were 58 percent more likely to develop congestive heart failure than men without the sleep apnea.
So now you know how important sleep is to heart health, what can you do?
- Avoid caffeinated drinks near bedtime
- Limit alcohol
- Find time to exercise during the day
- Turn off the computer, cell phone and television at least half an hour before going to sleep.
- Make quality sleep a priority
For those who have difficulty sleeping, fortunately, insomnia is treatable, explained Dr Wong. Sleep medications and supplements can be helpful, but mental and behavioral strategies must be implemented for best effects. First, identify and acknowledge your problem. See your doctor to rule out medical reasons including side effects of medications that may affect sleep. Then, learn how to change your behaviors to maximize sleep, manage your thoughts and worries that interfere with sleep, and change your mind-set about sleep.
By taking steps to achieve a healthy sleep pattern, you’ll feel better, sleep better and be doing your heart a favor.
- The impact of sleep disorders on glucose metabolism: endocrine and molecular mechanisms; Briançon-Marjollet et al Diabetol Metab Syndr. 2015; 7: 25. Published online 2015 Mar 24. doi: 10.1186/s13098-015-0018-3
- Adverse Impact of Sleep Restriction and Circadian Misalignment on Autonomic Function in Healthy Young Adults; Daniela Grimaldi, Jason R. Carter, Eve Van Cauter, Rachel Leproult
- Sleep duration predicts cardiovascular outcomes: a systemantic review and meta-analysis of prospective studies (Cappuccio, F., et al., European Heart Journal, June 2011; vol 32: pp 1484-92)
- Sidney, S., et al., Journal of the American Medical Association, December 2008; vol 300: pp 2859-2866