Sleeping late on weekends may up heart disease risk: study

Going to bed and waking up later on weekends than on week days may lead to social jet lag which is associated with an increased risk of heart disease, poorer health and worse mood, a new study warns.
According to researchers from the University of Arizona in the US, social jet lag has emerged as an important circadian marker for health outcomes.
Each hour of social jet lag is associated with an 11-per cent increase in the likelihood of heart disease.
These effects are independent of sleep duration and insomnia symptoms, which are related to both social jet lag and health.

"These results indicate that sleep regularity, beyond sleep duration alone, plays a significant role in our health," said lead author Sierra B Forbush, from the University of Arizona.
"This suggests that a regular sleep schedule may be an effective, relatively simple, and inexpensive preventative treatment for heart disease as well as many other health problems," said Forbush.

The research, led by senior author Michael A Grandner, analysed survey responses from 984 adults between the ages of 22 and 60 years.
Social jet lag was assessed using the Sleep Timing Questionnaire and was calculated by subtracting weekday from weekend sleep midpoint.

Overall health was self-reported using a standardised scale, and survey questions also assessed sleep duration, insomnia, cardiovascular disease, fatigue and sleepiness.
The American Academy of Sleep Medicine recommends that adults should sleep seven or more hours per night on a regular basis to promote optimal health.
In addition to adequate duration, healthy sleep requires good quality, appropriate timing and regularity.
The research was published in the journal Sleep.