We know that there are morning and evening people, but where does that difference come from? From your biological clock! This mini part of your brain controls the day and night rhythms in our body. Sunlight tells the clock that it is daytime, and puts our body into wake-up mode. The biological clock influences our behaviour but also the functioning of all kinds of processes in our body. It ensures a day and night rhythm, for example in our sleeping behaviour. Unfortunately, we do not always listen to what that clock has to tell us and we disrupt our biological rhythm. For example, when we work at night, travel to a distant country or shift the clock to daylight saving time. And that has consequences for our health.