Baker Institute study finds seven hours is best for sleep health

A study has revealed how long adults should be sleeping and how bad sleeping patterns can increase your risk of higher blood pressure and heart disease.

For the first time a new Victorian-led study has pinpointed the ideal time adults should sleep for good health.

Seven hours is optimal, according to the Baker Heart and Diabetes Institute.

Lead study author Morag Young says an hour less or more than for adults has a negative impact on blood pressure and heart health.

Sleep quality, she says, is equally important.

Associate Professor Young is a cardiovascular endocrinology laboratory head at the Baker Institute in Melbourne who worked on the study with PhD student Monica Kanki and the Bioinformatics team.

Associate Professor Morag Young from the Baker Heart and Diabetes Institute. Photo: Anna Carlile

Her study, published in Nature Communications, also found naps during the day and irregular sleeping patterns at night increased the risk.

The study reported that nightshift workers were particularly at risk and that the results were the same for women and men of all ages.

“What is important from this study is that we can show for the first time that sleep quality has an independent impact on overall health,” she said.

“Getting enough sleep, and keeping an eye on our sleep health is another important factor that, together with a good diet and exercise, helps to reduce the risk of higher blood pressure and heart disease.”

Napping during the day can mean you are not getting enough good quality sleep at night. Image: Supplied.

Associate Professor Young says the trigger is disrupted circadian rhythms. These rhythms are the body’s internal clock and regulate most processes in the human body including patterns of sleepiness, alertness and even appetite over 24 hours.

Maintaining the circadian rhythm of cellular functions is critical for good health and behaviours such as getting the right amount of sleep.

She said a novel finding was that the study showed an increase in markers of inflammation in people who don’t get enough sleep.

“And we are learning more these days that having low grade inflammation is not good for us in terms of heart health,” she said.

The team used health data from more than 420,000 adults who are part of the large and long-term UK Biobank cohort.

The study found night shift workers who slept less than five or six hours are most at risk of high blood pressure and heart disease. Image: Supplied.

“What we’ve found is that having circadian rhythms out of sync even slightly has an adverse impact on blood pressure,” Associate Professor Young said.

She identified that permanent night shift workers who slept less than five or six hours as most at risk, but said even workers on mixed shifts showed elevated blood pressure.

Sleeping longer on days off is not the solution as the study also found sleeping for too long had a disruptive effect.

“Key is going to bed at the same time each night, and waking up at the same time every morning,” Associate Professor Young said.

“Other experts have suggested getting your sleep on track is helped by getting up at the same time each morning and that napping during the day is often a sign that people aren’t sleeping well at night.”

Associate Professor Young said of concern from the study was that many were relatively young people with no early signs of cardiovascular disease.

“They were also in overall good health, but we still saw this effect of poor sleep on their blood pressure,” she said.

Sleeping longer on days off is not the solution. Image: Supplied.

Associate Professor Young said maintaining appropriate sleep lengths, of seven hours, and good sleep behaviours including going to be before midnight, could be an additional way to reduce the risk of developing hypertension.

“It is about bedding down good sleeping habits,” she said.

“We would also like to see when people are being assessed for risk of cardiovascular disease that their sleep health is also considered.

“Sleep should be considered part of healthy lifestyle management, up there with good diet and exercise and limited alcohol intake.”

Good sleep tips

• Go to bed and rise at the same time

• Get to sleep before midnight

• Aim for seven hours of quality sleep