A multitude of biological rhythms have been identified in the whole organism as well as within each living cell. Some of these rhythms reflect adaptations to our environment, while others run on their own. Recent evidence shows that these rhythms and their interaction might be more important not only for recreation but also for our health. Disturbance of the circadian rhythms by jet lag or shift work not only disturbs our metabolic balance but also increases the incidence of cancer. Rhythms in the organism obviously stabilize systemic functions: They increase organismic stability by calibrating the system's characteristics. Regulation curves in time and space are crucial for controlling physiological long-term stability. To be continuously aware of its properties an autopetic system may vary its parameters slightly over several time scales at different frequencies--akin to what our body does, e.g. in heart-rate variability.