Almost all cells regulate their biological processes over a 24-hour period, otherwise called a cell’s circadian rhythm. To do so, cells use a biological clock that cycles different genes on and off throughout the day and night. Scientists already know that our metabolic health can suffer when our biological clock breaks down, due to shift work or sleep disorders, for example. However, it’s unclear how exactly the biological clock of people with type 2 diabetes may differ from that in healthy people. Now a team of international scientists has shown that the skeletal muscle in people with type 2 diabetes has a different circadian rhythm. They argue that this might arise because of a communication breakdown between a cell’s time-keeping molecules and mitochondria, which produce chemical energy for cells. “The promise of this research is that it may help us to fine-tune the timing of interventions and other medications to treat type 2 diabetes, in order to optimize their effectiveness,” says Professor Juleen R. Zierath, PhD, from Karolinska Institutet and the Novo Nordisk Foundation Center for Basic Metabolic Research (CBMR) at the University of Copenhagen.