Going to sleep between 10 p.m. and 11 p.m. is associated with a lower risk of developing heart disease in comparison with earlier or later bedtimes, according to a study published Tuesday in the European Heart Journal — Digital Health. Research into the links between sleep and heart health often relies on foggy recollections or unreliable sleep diaries. Now, by attaching wrist-worn accelerometer devices to more than 88,000 people, they have been able more accurately to monitor sleep patterns and say they could have found an optimal bedtime to keep hearts healthy.
The body’s natural clock is responsible for setting the rhythm of our metabolism, learning and emotions, and “without it we’re a mess,” Plans said. He underscored that those who sleep late or work night shifts and unusual hours shouldn’t lament but should ensure they expose their eyes to “full-spectrum light” in the mornings.
Data on falling-asleep and waking-up times were collected over seven days using the wrist-worn accelerometers. The study found that around 3,172 participants (3.6 per cent) developed cardiovascular diseases — such as a heart attack, stroke or narrowed heart arteries. The rate of occurrences was highest in those with sleep times at midnight or later and lowest in those who fell asleep between 10 p.m. and 10:59 p.m.
There was a 25 per cent higher risk of cardiovascular disease among those who fell asleep at midnight or later vs. those who fell asleep between 10 p.m. and 10:59 p.m. and a 24 per cent raised risk of falling asleep before 10 p.m., the research found.
After taking into account various information, such as participants’ age, sex, smoking status, duration of sleep, sleep irregularity, whether they had diabetes, their blood pressure and socioeconomic status, the researchers found participants who fell asleep between 10 pm and 10:59 pm had a lower risk of cardiovascular disease than those who dozed off earlier or later.
More specifically, those who fell asleep at midnight or later had a 25% higher risk of going on to develop cardiovascular disease, while those who fell asleep before 10 pm had a 24% increased risk. Even nodding off an hour later was linked to a difference – those falling asleep between 11 pm and 11:59 pm had a 12% greater risk of cardiovascular disease than those who fell asleep in the hour before. The team say the findings appear to be stronger in women than men, although the reasons for this remain unclear.
The study has limitations, including that it is based only on data from adults aged 43 to 79, and participants of the UK Biobank – a database of genetic and lifestyle information that researchers are using to investigate myriad health issues – are predominantly white. Plans said further research, with larger numbers of participants, is needed to examine the findings, adding there was not enough evidence at present to prescribe a particular bedtime to the public. However, he said the study added support to the importance of sleep hygiene – habits that help with a good night’s rest.
“People often assume that cardiovascular disease is a consequence of physiological influences,” Plans said. “Whereas actually, the behavioural influence on the cardiovascular system as a result of circadian disruption is enormous.”
If you have an underlying heart issue that´s being compounded by your inability to fall asleep or stay asleep, contact us here at ISD Health Solutions for a free assessment.