Even a single night’s sleep deprivation can change the genes that control the biological clocks in our cells.
Swedish researchers studied 15 healthy men who came to the lab for two nights on two separate sessions.
The participants had one night’s sleep and were kept awake the other night.
Light conditions, food intake and activity levels in the lab were controlled and they were bed-restricted when kept awake.
Small tissue samples from the muscle on the thigh and the superficial fat on the stomach were taken.
These tissues are important for controlling blood sugar levels and regulating metabolism.
The analyses of the collected tissue samples showed alterations in regulation and activity of clock genes only after a single night’s sleep loss.
Dr Jonathan Cedernaes, the lead author of this study, explains:
“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.
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.”
The activity of genes is regulated by a mechanism called epigenetics.
This involves chemical changes to the DNA molecule such as methylation which regulates how the genes are switched on or off.
Dr. Cedernaes says:
“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.”
However, the researchers observed that the changes in the tissue samples were different.
“This could suggest that these important molecular clocks are no longer synchronized between these two tissues.
As such, ‘clock desynchrony’ between tissues has been linked to metabolic pathologies, this could suggest that these tissue-specific changes were linked to the impaired glucose tolerance that our participants demonstrated after the night that they had been kept awake.”
At this stage it is not yet clear how persistent these changes are, as Dr Cedernaes points out:
“It could be that these changes are reset after one or several nights of good sleep.
On the other hand, epigenetic marks are suggested to be able to function a sort of metabolic memory, and have been found to be altered in e.g. 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.”
This study was published in The Journal of Clinical Endocrinology & Metabolism (Cedernaes et al., 2015).
Poor sleep image from Shutterstock