Day-night rhythm disturbance is a very common condition in the Western world. People doing shift work are a well-known example of this, but people who work, watch television or eat until late at night can also disturb their day-night rhythm. This influences our biological clock, which is located in all organs of the body. This clock prepares the body for our normal behaviour, like eating, sleeping and activity. Over the last few years, it has become apparent that a disturbed circadian rhythm is linked to an increased risk of obesity, type 2 diabetes mellitus, and cardiovascular diseases, among other things. However, the mechanism behind this increased risk has not yet been fully explained.

In this study, the researchers tested whether the metabolism that takes place in our muscles, where most of the carbohydrate combustion takes place, follows a day-night rhythm. It turns out that both the muscle metabolism and a person's energy use at rest are at their highest at 11 o'clock at night.

Follow-up research will address the question of whether the day-night rhythm of the muscles can indeed be disturbed and whether there is a disturbed circadian rhythm in the muscles of people suffering from obesity or type 2 diabetes mellitus. With the findings of this study, we hope to be able to define new recommendations (or develop new medication) that can help maintain the day-night rhythm in the muscles.

The study, published and available online in the August edition of Molecular Metabolism, was performed by Dirk van Moorsel and Jan Hansen under the supervision of Prof. Patrick Schrauwen of the NUTRIM School of Nutrition and Translational Research in Metabolism at Maastricht University/Maastricht UMC+.