Telling a teenager to go to bed early is often a thankless task, typically met with eye rolls and protests.
But scientists say getting a few extra hours of shut-eye could protect youngsters against serious long-term health risks such as type 2 diabetes and obesity.
Researchers from the University of Copenhagen found teens who got even just one extra hour of sleep had fewer fluctuations in their blood sugar levels.
This is important because large swings in blood sugar – scientifically referred to as glucose – can trigger inflammation and place pressure on the body’s metabolic systems. Over time, this can increase the risk of developing serious health conditions like obesity and diabetes.
The number of young people with diabetes has surged globally, with cases doubling over the past 30 years. In England, almost 1,600 children are living with type 2 diabetes – caused by having overly high blood sugar levels.
While a link between sleep and metabolic disease such as diabetes is not new, most previous research has focused on middle-aged adults or people already at increased risk of the condition.
Authors of the new research, published in the journal SLEEP, however, say their findings suggest that it can also affect young people.
Professor Morten Arendt Rasmussen, from the department of food science at the University of Copenhagen, and the study’s senior author, said: ‘We already know that sleep is important for mental well-being. Our study adds to our understanding of why sleep is also crucial for physical health – and that this applies even early in adulthood.
Teenagers sleeping for longer could be protected against serious health complications like type 2 diabetes and obesity, scientists say
‘It also highlights that many of the health problems we tend to see later in life may actually be established much earlier than we previously thought.’
The researchers conducted the study by tracking 206 18-year-olds in Denmark for around two weeks using devices that monitored movement, sleep and blood sugar levels.
For every extra hour of sleep, the teens’ glucose became more stable, with fewer day-to-day fluctuations.
Meanwhile, average blood sugar rose slightly – by 0.39 milligrams per decilitre mg/dL – a unit which measures blood sugar levels in some nations outside the UK.
Although a rise in blood sugar may not sound like an improvement, it was accompanied by a lower risk of dangerous highs and lows. This suggests overall healthier blood sugar regulation.
Professor Rasmussen explained: ‘For most 18-year-olds, diabetes feels like something far off in the future.
‘We’ve known very little about what blood sugar variability means for this age group. But here we’re seeing similar patterns even in completely healthy young adults.’
The research also found that teenagers whose blood sugar fluctuated more during the day tended to sleep for almost seven minutes less the following night, suggesting sleep and blood sugar influence one another.
David Horner, a postdoctoral researcher from the University of Copenhagen, and the study’s first author, said: ‘So this appears to be a two-way relationship – and that’s new.’
Researchers were also surprised to find that longer sleep was associated with higher blood sugar levels during the morning.
But Professor Rasmussen believes this ‘may actually be beneficial’ because it could ‘help curb sugar cravings and thereby contribute to more stable blood sugar overall’.
Although the study cannot prove that longer sleep directly causes healthier blood sugar regulation, the researchers say it suggests that relatively simple lifestyle changes could have long-term health benefits.
Professor Rasmussen said: ‘If future studies confirm our findings, sleep could become an even more important factor in preventing disease and promoting health among young people.
‘And taking action doesn’t require a new diet or an expensive gym membership – it really just comes down to going to bed.’
Around 4.7 million people in the UK are living with a diabetes diagnosis, although Diabetes UK estimates almost 1.3 million have undiagnosed type 2 diabetes.
Left unmanaged type 2 diabetes can lead to life-altering complications such as heart attacks, strokes, blindness and limb amputations.