Sleep, Circadian Rhythms and Lifelong Health

Sleep and daily rhythms emerge from our genetics, physiology, behaviour and the environment. Like most of our behaviours, they are not fixed. These rhythms are modified by our actions, how we interact with the environment, how we progress from birth to old age, and if we experience illness.

From infancy to advanced adulthood, our body clock and sleep patterns change profoundly. While the variation in our sleep and circadian rhythms can be very marked between individuals, some trends can be considered universal:

• the amount of time we spend asleep (sleep duration) shortens as we age;
• our circadian rhythms become less 'robust', and provide a weaker drive for our 24-hour biology, including sleep which can become more fragmented;
• there is a change in our circadian timing, with a tendency to show a later chronotype as we progress through the teenage years and into early adulthood, and then shifting increasingly to an earlier chronotype, beginning in our twenties and continuing into old age.

As we age many of us feel we don’t get the sleep we want or need. How these changes occur is not fully understood, but the impact of increasing levels of sleep and circadian rhythm disruption (SCRD) is increasingly recognised as a problem in both adolescents and the elderly. By building our knowledge in this area of sleep and circadian biology, we can begin to develop evidence-based and condition-specific treatments for the amelioration of SCRD across the life span.