Nobody likes missing out on a full night's sleep, but it's something lots of us have to contend with from time to time. For shift workers, it's par for the course to have your sleep patterns messed around by your job. Students regularly pull all-nighters when cramming for exams (or when celebrating after), and people with sleeping disorders may be more used to sleepless nights than well-rested ones.
However, a new study has found that going without sleep may have deeper implications for our bodies than scientists previously thought. Researchers at Uppsala University and the Karolinska Institute in Sweden have discovered that losing just a single night of sleep can alter the genes that control our body's cellular biological clocks.
The researchers took 15 healthy male volunteers and had them visit their laboratory on two separate occasions, with each stay lasting for two nights. On the first night of each session, all participants enjoyed a regular night's sleep (over 8 hours).
On the second night, they either slept again or were deprived of sleep while being kept to their beds, with each volunteer experiencing one night of total sleeplessness. Blood and tissue samples were taken before and after the enforced all-nighters.
Once the samples were analysed, the researchers found that the regulation and activity of volunteers' clock genes had been altered after a single night of sleep loss. The samples taken from sleep-deprived participants showed increased evidence of epigenetic activity - chemical alterations to the DNA molecule that regulate which genes are switched on or off - plus a change in the level of gene expression being processed.
"As far as we know, we are the first to directly show that epigenetic changes can occur after sleep loss in humans, but also in these important tissues," said Jonathan Cedernaes, lead author of the study, in a statement. "It was interesting that the methylation of these genes could be altered so quickly, and that it could occur for these metabolically important clock genes."
The findings, to be published in the Journal of Clinical Endocrinology and Metabolism, are important because of the links scientists have already found between how much sleep we get and how predisposed we are to risks of various metabolic diseases.
"Previous research has shown that our metabolism is negatively affected by sleep loss, and sleep loss has been linked to an increased risk of obesity and type 2 diabetes," said Cedernaes. "Since ablation of clock genes in animals can cause these disease states, our current results indicate that changes of our clock genes may be linked to such negative effects caused by sleep loss."
At this point, the researchers don't know how long the gene alteration takes affect for. While there's a hope that any adverse affects might not be long-lasting, the potential for greater risks in the longer term means it's worth trying to stick to as regular a sleep schedule as possible until further research can provide the answers.
"It could be that these changes are reset after one or several nights of good sleep," said Cedernaes. "On the other hand, epigenetic marks are suggested to be able to function [as] a sort of metabolic memory, and have been found to be altered [in] shift workers and people suffering from type 2 diabetes. This could mean that at least some types of sleep loss or extended wakefulness, as in shift work, could lead to changes in the genome of your tissues that can affect your metabolism for longer periods."