Doctor Q&A: Sleep is Essential for a Healthy Heart

Important not only for your overall well being but also for a healthy heart, Dr Nandakumar talks to us about the importance of sleep

If you are missing out on your daily dose of zzz’s, it is time to make a change. 

With sleep being a major component of a healthy lifestyle, doctors are increasingly urging everyone to get enough hours asleep. From countering modern day illnesses to maintaining heart health, Dr Nandakumar talks to us about the importance of sleep. So, read on and press down on that snooze button to get some extra hours in.

What is the optimum amount of sleep one needs?

The National Sleep Foundation recommends, 8 hours on an average for adults with a range of 6 to 10 hours. In the elderly this changes to a range of 5.5 hours to 9 hours with 7.5 hours average.1 In a nutshell, I would say get as much sleep as you can to wake up refreshed the next morning with a minimum of 7-8 hours.

How is sleep linked to our overall health?

In the general scheme of things, sleep is probably the last thing on your mind. And yet, countless research and medical studies have found a link between lack of sleep (or less than optimum hours) and serious health problems like diabetes, heart disease and consequently heart attacks. Essentially sleep deprivation can cause high blood pressure or hypertension, heart disease (both directly and indirectly through hypertension and diabetes) and diabetes mellitus or high blood sugar. It also appears that sleeping well confers longevity as seen in several longitudinal prospective studies.

Heart health and sleep specifically, what’s the connection?

Sleep seems to have a cascading effect on your health and eventually heart health. Lack of sleep appears to disrupt processes like glucose metabolism, blood pressure and inflammation.

Sleep is essential for a healthy heart, so much so that some studies suggest that those who slept fewer than six hours per night were about twice as likely to have a stroke or heart attack as people who slept six to eight hours per night.2

Short sleep duration is associated with the development of hypertension or high blood pressure. Multiple studies have shown that certain hormones called sympathetic hormones increase after sleep deprivation with high heart rate. Sleep deprivation also causes increased psycho-social stress that eventually leads to increased salt intake and decreased renal salt excretion.3 Several studies have in fact,  found that sleep deprivation causes increased risk of cardiac heart disease and mortality due to heart related diseases.4

Does a power nap actually work?

Eyeing that super fancy sleep pod in your office? The answer to whether power naps actually work is yes – mostly! A short quick nap is likely to help with alertness, enhance performance as well as reduce mistakes5. However, do not let a short nap become a long episode of sleep as you may end up with a grogginess that is not perfect for work or any performance!

Looking at finishing some work late night? Choose a short nap over that coffee. A study in 2008 showed that naps work better than caffeine when it comes to improving verbal memory, motor skills and learning.

What is the best time to go to sleep?

While I would like to say that you should start winding down by 9pm, and talk about light vs. deep sleep, sometimes that’s just not feasible. An easier way to look at this is to calculate backwards from the time you need to be up in the morning. Go back 8 hours from the time you need to set the alarm, add about half an hour for your body to get used to sleep mode and voila that’s a doable magic number. Also, what’s particularly important is that you maintain your sleep and waking up time – weekday or weekends.

What advice do you have for troubled sleepers?

Simple lifestyle changes, meditation and sleep inducing apps can help you remarkably. I would recommend no caffeine after 6pm and avoid alcohol and tobacco before bedtime. Exercise too should ideally be early in the day versus later.

Sunday nights can be the worst nights to switch off and get a good night’s sleep if you are thinking of work or school the next day, so plan an early night with TV or a good book to take your mind off things.

Keep stress levels down by monitoring your room temperature, lighting and the general mood. There are several apps that can help with relaxing music to help with winding down. And did I mention no phones? No phones or surfing Facebook before you sleep!

About Dr Nandakumar

Dr Nandakumar is currently working as a Senior Interventional Cardiologist at Cardiac Centre International and Mount Elizabeth Hospital Novena. He also visits at , Gleneagles Hospital, Farrer Park Hospital and Mount Alvernia Hospital. He is also a Visiting Senior Consultant at Ng Teng Fong Hospital and National University Hospital. You can reach Dr Nandakumar on +65 82616483 or via his website


National Sleep Foundation’s sleep time duration recommendations: methodology and results summary. Hirshkowitz, Max et al. Sleep Health: Journal of the National Sleep Foundation , Volume 1 , Issue 1 , 40 – 43

Tochikubo O, Ikeda A, Miyajima E, Ishii M. Effect of insufficient sleep on blood pressure monitored by a new multi biomedical recorder. Hypertension 1996

A prospective study in the United States showed that the standardized mortality ratio of CHD was highest among those who worked 67 hr or more a week [28]. */* [28] Buell P, Breslow L. Mortality from coronary heart disease in California men who work long hours. J Chorn Dis 1960; 11: 615- 26.

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