After a busy work week many adults find themselves craving a little extra shut-eye.
However, a growing body of research indicates sleeping in on the weekends can cause what’s known as ‘social jet lag’, a condition with effects that mirror those of traditional jet lag: poorer health, worse mood, increased sleepiness and fatigue.
Social jet lag occurs when the body’s internal clock doesn’t match up with a person’s sleep schedule.
We asked one of the leading researchers in the field Michael Grandner, PhD, how much sleep-in time the average person can get away with on the weekend before social jet lag becomes an issue.
Surprisingly, he said that sleeping in for two hours or fewer may not be a problem.
A growing body of research indicates sleeping in on the weekends can cause ‘social jet lag’, which has been linked to poorer health, worse mood, sleepiness and fatigue
‘Our data suggest that if the midpoint of your sleep moves by more than an hour, you may be at increased risk,’ the professor from University of Arizona told Daily Mail Online.
‘So that would mean going to bed an hour later and waking up an hour later, or even going to bed two hours later and waking up at the same time.’
More than a third of American adults don’t get the recommended seven to eight hours of sleep every night.
Sleep deprivation can decrease productivity during the day and lead to long-term health problems such as diabetes, obesity, and even heart disease.
However there is increasing evidence that suggests having a consistent sleep schedule is just as important as getting enough hours of sleep.
‘If you’re pretty severely sleep deprived, some sleeping in may mitigate some of the damage,’ Grandner said. ‘But if you’re less sleep deprived, the benefits may be outweighed by the schedule shift.’
A Northeastern Illinois University study published Wednesday looked specifically at how the social jet lag phenomenon affects students.
Out of nearly 15,000 students, only four in 10 appeared to have body clocks that were naturally synchronized with their academic schedules.
The remaining 60 percent students suffered from social jet lag of at least 30 minutes.
The problem is worst among natural ‘night owls’ – those who would naturally wake up later than their schedules allow.
The majority of the students suffering from social jet lag advanced their activity on class days, meaning that they got up and starting doing things earlier.
A small subset, however, delayed their activity on class days.
The social jet lag was found to negatively impact academic performance and exam grades across the board.
The negative impact was less severe in those who delayed activity.
A lead researcher on the study, Aaron Schirmer, said that the American school system tends to favor ‘morning larks’ – those who naturally wake up earlier – as opposed to night owls.
‘The benefits to individuals and societies stemming from enhancing education by enabling individuals to take advantage of their own biological rhythms are surely substantial,’ he said.
Previous research has shown that people whose body clocks are out of sync with their work and social schedules are more likely to be depressed, smoke cigarettes and drink alcohol.
A 2017 study by the University of Arizona even found that each hour of social jet lag increased the likelihood of heart disease by 11 percent.
‘It was particularly surprising that these effects were independent of how much sleep people got and any insomnia symptoms,’ lead author Sierra Forbush said.
‘These results indicate that sleep regularity, beyond sleep duration alone, plays a significant role in our health.’