Men who want to go to bed early could be showing a warning sign of heart problems, medical professionals warned.
A study of 2,400 adults revealed that among men, those who suffered from high blood pressure had bed times significantly earlier than their healthy peers.
People who suffered from the condition - one of the key risks for heart disease - retired for the night 18 minutes earlier than those without it.
The Japanese study further found that of those who went to bed early, people with high blood pressure were significantly more likely to spend the night tossing and turning.
While early turn-ins were linked with higher blood pressure, getting more sleep was not likely to help the condition, they cautioned.
According to WHO figures, raised blood pressure was estimated to cause 7.5 million deaths globally.
A quarter of all adults in the UK had high blood pressure, also known as hypertension, but many people were completely unaware they were at risk.
The condition, which upped the risk of heart attacks, stroke and dementia, can be easily treated with drugs or by simple changes to lifestyle.
However, as high blood pressure had few symptoms until it was too late, people simply had no idea they had a problem until they were tested or fell ill.
Presenting his findings at the European Society of Cardiology congress in Rome, Hiroshima University researcher Nobu Sasaki said: "Early bed times were associated with hypertension, independent of anything else."
He added, those with high blood pressure may prefer earlier nights due to their worse underlying health which made them more tired.
He added it was also possible that their internal body clock known as the circadian rhythm had shifted which left them tired in the evenings but kept them awake at night.