How losing a night's sleep loss can cost your body

Scientists have shown that not sleeping for a night can alter the genes that control the biological clocks in cells throughout our body.

Jonathan Cedernaes, lead author on the study and a researcher at Uppsala University, said that previous research had shown that our metabolism was 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 the disease states, their current results indicate that changes of clock genes may be linked to such negative effects caused by sleep loss, he added.

Molecular analyses of the collected tissue samples showed that the regulation and activity of clock genes was altered after one night of sleep loss. The activity of genes is regulated by a mechanism called epigenetics. This involves chemical alterations to the DNA molecule such as methyl groups - a process called methylation - which regulates how the genes are switched on or off. The researchers found that clock genes had increased numbers of such DNA marks after sleep loss. They also found that the expression of the genes, which is indicative of how much of the genes' product is made, was altered.

Cedernaes claimed that their research was the first to directly show that epigenetic changes could occur after sleep loss in humans, but also in the important tissues.

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, he continued.

The changes that the researchers observed were however different in the adipose tissue and the skeletal muscle, which they said could suggest that these important molecular clocks were no longer synchronised between the two tissues.

It also suggested that these tissue-specific changes were linked to the impaired glucose tolerance that the participants demonstrated after the night that they had been kept awake.

Cedernaes pointed out that at least some types of sleep loss or extended wakefulness, as in shift work, could lead to changes in the genome of tissues that could affect metabolism for longer periods.

The study is due to be published in the Journal of Clinical Endocrinology and Metabolism.