Is there a “golden hour” to go to sleep that reduces your risk of heart disease? (2024)

Headlines have suggested that bedtimes between 10pm and 11pm are best for your heart. Is this backed up by science? We investigate.

Updated 10 August 2023

According to research published in the European Heart journal, going to sleep between 10pm and 11pm is linked to a lower risk of heart and circulatory disease.

The study used data from over 88,000 UK Biobank participants aged 43-74, who were monitored over the course of a week. They answered questions about their lifestyle and wore a wrist tracker which recorded what time they fell asleep and woke up. Over the next six years, 3,172 of them developed heart and circulatory disease.

Once the results had been adjusted to take account of age, smoking, and other risk factors for heart and circulatory disease, the people who fell asleep between 10pm and 11pm had the lowest risk of heart and circulatory disease. In comparison, people who fell asleep between 11pm and midnight had a 12 per cent greater risk of developing heart and circulatory disease, and those that fell asleep at midnight or later saw this risk increase by 25 per cent.

The researchers also found that time of going to sleep appeared to make more of a difference to heart and circulatory disease risk in women than men.

They suggested that sleep timing could be a previously overlooked risk factor for heart and circulatory disease, perhaps because going to sleep at the right time means you are more likely to wake up with the morning light, which could help set your body’s circadian rhythms. There is some evidence that disrupted circadian rhythms can increase your risk of heart disease and its risk factors, such as high blood pressure. They say that further research is required in this area.

How good was the research?

Whilst the study was well-designed, this type of research cannot prove direct cause and effect. This means that although sleep timing was linked to heart disease, this doesn’t mean we can say for sure that one causes the other.

The time at which people fall asleep might be linked to other health conditions or unhealthy habits which increase their risk of developing heart and circulatory disease, such as drinking.

In addition, the study only measured the time people fell asleep in a one-week period. This might not have been long enough to capture natural variations in sleep, and it could have changed during the follow-up period. The researchers also only monitored the length and timing of peoples’ sleep, not the quality. This might be another important factor for heart health.

While a strength of this study was the large number of participants, they were mostly individuals from a white British background. The researchers acknowledged that this was a limitation, and called for further research using a more diverse range of participants.

Lastly, while the research suggests that going to sleep between 10pm to 11pm is better than earlier or later, there were a relatively small number of people who fell asleep earlier than 10pm, so the evidence for this is more limited.

It seems that more research is needed before we can advise people to change their bedtime.

How good was the media coverage?

The study was covered by national newspapers and sites such as The Metro, The Mirror and The Daily Record.

Generally, the headlines made this research sound more definitive than it really was. For example, The Metro headline was: “This is the best time to go to sleep to protect your cardiovascular health”.

The Daily Record headline was also misleading, stating: “The exact time you should fall asleep every night to reduce risk of ‘silent killer’”. The Mirror headline was worded similarly, using the phrase ‘exact time’ and the word ‘should’.

The problem with these headlines is that they dress up possibilities as facts. It’s possible that a bedtime of 10pm to 11pm leads to better heart health, but we cannot say for sure based on the findings. These types of study are only designed to show links between two things rather than cause and effect relationships. By making a direct recommendation to change our behaviour, these headlines are making things seem black-and-white.

The BHF verdict

Regina Giblin, Senior Cardiac Nurse at the British Heart Foundation, said:

“This large study suggests that going to sleep between 10 and 11pm could be the sweet spot for most people to keep their heart healthy long-term.

“However, it’s important to remember that this study can only show an association and can’t prove cause and effect. More research is needed into sleep timing and duration as a risk factor for heart and circulatory diseases.

“Getting enough sleep is important for our general wellbeing as well as our heart and circulatory health, and most adults should aim for seven to nine hours of sleep per night.

“But sleep isn’t the only factor that can impact heart health. It’s also important to look at your lifestyle as knowing your numbers such as blood pressure and cholesterol levels, maintaining a healthy weight and exercising regularly, cutting down on salt and alcohol intake, and eating a balanced diet can also help to keep your heart healthy.”

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