Going to bed at the same time each night could have benefits for the heart and metabolism, a US study suggests. Getting good quality sleep has long been linked to improved health, while sleep irregularity is thought to be linked to obesity and an increased risk of type 2 diabetes.
Scientists from the Duke University Medical Center, based in North Carolina, studied the sleeping patterns of almost 2,000 people aged 54-93, none of whom had any history of sleep disorders.
The participants wore devices for seven days which tracked their variations in sleep patterns, and also kept a sleep diary.
The researchers then examined links between sleeping patterns and a series of cardiometabolic risk markers, and projected a 10-year projected risk for heart disease, obesity, high blood pressure and type 2 diabetes.
People with irregular bedtimes were shown to have a higher body mass index (BMI), increased blood sugar levels, higher blood pressure and higher HbA1c levels.
Also, the study participants with inconsistent sleeping patterns – who went to bed and woke up at varying times – had an increased risk of a heart attack or stroke in the next ten years, compared with people who went to bed and got up at more consistent times.
This group of people also had a greater risk of depression and stress, compared with the people who had regular sleeping hours.
The research team however said that their study was observational and the results did not relate to causality. But they did suggest sleep irregularity “may represent a target for early identification and prevention of cardiometabolic disease”.
“From our study, we can’t conclude that sleep irregularity results in health risks, or whether health conditions affect sleep. Perhaps all of these things are impacting each other,” said study author Dr Jessica Lunsford-Avery.
“Perhaps there’s something about obesity that disrupts sleep regularity. Or, as some research suggests, perhaps poor sleep interferes with the body’s metabolism which can lead to weight gain, and it’s a vicious cycle.”
Dr Lunsford-Avery said the team wanted to carry out further research to investigate the biology of sleeping and the influence of bedtimes.