New research shows the optimal bedtime to promote good heart health is between 10 p.m. and 11 p.m.
That’s according to U.K. Biobank cohort published last month in the European Heart Journal.
A group of U.K. researchers monitored the sleep and wake times of 88,026 adults over seven days, using an accelerometer device.
The researchers monitored the participant’s cardiovascular health over 5.7 years.
The study found that the risk of developing cardiovascular disease is up to 38 per cent higher if you go to sleep earlier than 10 p.m. or later than 11 p.m., even after adjusting for factors such as sleep quality, age and other diseases.
According to the study, 3,172 of the participants developed cardiovascular disease (CVD).
Of those people, 1,371 or 43 per cent had a bedtime after midnight, while 1,196, or 38 per cent, had a bedtime between 11 p.m. and 11:50 p.m.
Of the participants who developed CVD, 473, or 15 per cent went to bed between 10 and 10:59 p.m., and 132 (4.2 per cent) had a bedtime before 10 p.m.
The study also found that the effect of sleep-timing was especially significant in women.
Dr. Melissa Lem is a Vancouver family physician. She told CTV’s Your Morning that between 10 p.m. and 11 p.m. is the optimal bedtime because of your body’s internal clock.
She said if you wake up too early or too late, you might not see morning light at the right time, which is “really important for resetting your body clock -- or your circadian rhythm.”
“And there's a lot of evidence also showing that unhealthy sleep is related to other cardiovascular conditions, like obesity, diabetes, and high blood pressure with later bedtimes in particular increasing your risk of a high body mass index,” Lem said. “And overtime, all of these things can worsen your heart health.”
WHAT IS THE OPTIMAL WAKE UP TIME?
When it comes to the optimal wake up time, Lem said the “research is mixed.”
She said some studies show that staying on the same sleep schedule – meaning waking up at the same time every day – is best, because sleeping in can make you feel jet-lagged.
“But others show that people who catch up on their sleep with an extra one to two hours on the weekend live just as long, as they make up that sleep deficit that they accumulate during the work week,” she said.
Lem said in general, sticking to the same sleep schedule and wake-up time “is best.”
However, she said it’s fine to sleep in occasionally.
HOW MUCH SLEEP IS IDEAL?
Lem said the “general scientific consensus” says that getting between seven to nine hours of sleep per night is “ideal.”
“Sleeping less than seven hours is linked to all kinds of different health issues like depression, heart disease, stroke and diabetes,” she said. “And if you’re sleeping more than nine hours per night, this could be an indication that you have some diseases that are making you tired that can also shorten your life expectancy.”
Lem said they key is to prioritize sleep, adding that it’s just as important as eating well and exercising.
She said in the winter or holiday season, people should get lots of sunlight and spend as much time outdoors as possible to help “reset your body clock.”
Avoiding caffeine in the afternoon and avoiding alcohol in the evenings is helpful too, Lem said.
“And then finally, avoiding screen time for at least one hour before bedtime because that blue light actually tricks your brain into thinking it’s daytime,” she said.
