Adolescent boys who experience what is called slow-wave sleep after sleep deprivation may have a significantly higher chance of developing insulin resistance.
They may be also at greater risk for developing type 2 diabetes, increased visceral fat and impaired attention.
Slow-wave sleep (SWS) is an important stage of sleep involved in memory consolidation and recovery after sleep deprivation, and is also associated with reduced cortisol and inflammation.
According to Jordan Gaines, a Penn State neuroscience researcher, boys who experience a greater decline in slow-wave sleep as adolescents have a significantly higher chance of developing insulin resistance than those who more closely maintained their slow-wave sleep as they got older.
“On a night following sleep deprivation, we’ll have significantly more slow-wave sleep to compensate for the loss,” said Gaines, a doctoral candidate in neuroscience, College of Medicine.
“We also know that we lose slow-wave sleep most rapidly during early adolescence. Given the restorative role of slow-wave sleep, we weren’t surprised to find that metabolic and cognitive processes were affected during this developmental period.”
Gaines analyzed results collected through the Penn State Child Cohort in order to study long-term effects of SWS loss from childhood to adolescence.
The cohort included 700 children from the general central Pennsylvania population, age five to 12. Eight years later, 421 participants were followed up during adolescence – 53.9% were male.
Participants stayed overnight both at the beginning of the study and at the follow-up and had their sleep monitored for nine hours. At the follow-up appointment, participants’ body fat and insulin resistance were measured, and they also underwent neuro-cognitive testing.
Gaines found that in boys, a greater loss of SWS between childhood and adolescence was significantly associated with insulin resistance, and this loss was marginally associated with increased belly fat and impaired attention.
However, Gaines did not find any associations between SWS and insulin resistance, physical health or brain function in girls.
Importantly, the participants’ sleep duration did not decline significantly with age, suggesting that the effects observed were due to a loss of this “deeper” stage of sleep, according to the researcher.
Meanwhile, earlier research found that one night of sleep deprivation and six months on a high-fat diet could both impair insulin sensitivity to a similar degree.
This study, conducted by Josiane Broussard, PhD, and colleagues from Cedars-Sinai Medical Centre in Los Angeles, used a canine model to examine whether sleep deprivation and a high-fat diet affect insulin sensitivity in similar ways.
When the body becomes less sensitive to insulin, it needs to produce more insulin to keep blood sugar stable. This may eventually lead to type 2 diabetes, a disease where the body’s insulin response doesn’t work properly and there is too much sugar in the blood.
“Research has shown that sleep deficiency and a high-fat diet both lead to impaired insulin sensitivity but it was previously unknown which leads to more severe insulin resistance,” said Broussard.
“Our study suggests that one night of total sleep deprivation may be as detrimental to insulin sensitivity as six months on a high-fat diet. This research demonstrates the importance of adequate sleep in maintaining blood sugar levels and reducing risk for metabolic diseases like obesity and diabetes.”
To conduct the study, the researchers measured insulin sensitivity in eight male dogs before and after diet-induced obesity.
Prior to the high-fat feeding, researchers used an IV glucose tolerance test to measure insulin sensitivity in dogs that had one night of sleep deprivation, and compared results to dogs that had a normal night’s sleep.
The dogs were then fed a high-fat diet for six months, at which point they were tested again. Prior to the high-fat diet, one night of sleep deprivation reduced insulin sensitivity by 33%; this reduction was similar to the reduction caused by a high-fat diet alone (21%).
Once the dogs had impaired insulin sensitivity from the high-fat diet, one night of sleep deprivation did not further impair the insulin sensitivity.