Your bedtime could put your heart at risk

I’m what you would call a night-time person. I haven’t gone to bed before midnight for years, let alone before 11pm. This would not be a problem in my eyes if my post-midnight hours were productive, but they rarely are. For some time now I’ve harboured hopes of becoming an early bedtime person, but motivation has escaped me – until now.

I’d always suspected that my nocturnal hours weren’t great for my health. Now, a study that’s come to my attention has slapped me in the face with confirmation of that suspicion. And the reality of it goes straight to the heart – literally.

Published in the European Heart Journal, the study shows a correlation between post-midnight bedtimes and an increased risk of heart disease. And it’s not just a slight increase. The risk factor rose by 25 per cent. 

That’s the sort of number that might almost be enough to scare me into going to bed earlier – much earlier. 

Could your bedtime actually be too early?

But before I make any radical change, I should make sure I understand any other risks that it could introduce. As it turns out, there are. To my surprise, the study reveals your risk of heart attack also increases if you go to bed before 10pm.

What’s more, the increase in risk is almost as high as for post-midnight bedtimes, coming in at 24 per cent. This seems almost contradictory, but the research sample size was solid, taking in sleep data from just over 88,000 adults.

The study participants’ sleep times were recorded using a device worn on their wrists called an accelerometer. Their fall-asleep and wake-up times were collected over a seven-day period. Other assessments and questionnaires recorded potential factors such as demographics, health, and lifestyle.

After a follow-up period of 5.7 years on average, the researchers revisited the participants, recording any diagnoses related to heart disease. It was through analysis of this follow-up data that they were able to correlate the risk levels with bedtimes. 

Narrowing the golden window

It’s pretty clear, then, that heading off to bed before midnight is a good idea. On the other hand, hitting the pillow before 10pm is not. The optimal window would therefore seem to be the two hours between 10pm and midnight.

However, the researchers were able to narrow down that time frame further. Going to bed between 11pm and midnight is certainly associated with a lower risk, but the ‘golden’ hour is 10-11pm.

In fact, heading to bed within that hour is actually associated with a lower risk of developing heart disease.

For me, this is certainly food for thought although, as always, we must remember that correlation doesn’t always mean causation. Study author David Plans PhD, put it eloquently. “While we cannot conclude causation from our study, the results suggest that early or late bedtimes may be more likely to disrupt the body clock, with adverse consequences for cardiovascular health.”

He’s right, of course, and I can draw on my own experience to back that up. My post-midnight activities will often include snacks, generally not of the healthy variety. For those in the study with similar habits, it could be these that are contributing to the risk.

Either way, if I notice I’m still up at 11pm tonight, I will very seriously consider going straight to bed. Or, at the very least, staying away from the pantry and fridge.

Are you a night-time person? What’s your usual bedtime? Let us know via the comments section below.

Also read: Why too many Aussies are not getting enough sleep

Disclaimer: This article contains general information about health issues and is not advice. For health advice, consult your medical practitioner.