The quality, timing and length of sleep are dependent upon an interaction between two biological systems in our brain. Our body clock drives daily patterns called circadian rhythms, while a sleep monitor, called the sleep homeostat, acts like an egg timer, tracking how long we are awake. Particular groups of cells in the brain are involved in maintaining a wake state, whilst others induce sleep.
It’s not hard to disrupt the balance, as most of us don't have a regular sleep routine. We mix early starts, late nights and weekend lie-ins. We travel across time zones, teenagers stay out late and older people are sometimes confined indoors where there is insufficient light. When these systems get out of sync, we can suffer insomnia, sleep phase disorders and other problems like waking too early or poor quality sleep.
Healthy sleep through light therapy
Light is able to synchronise our internal clock and regulate the brain cells that produce sleep or wakefulness hormones to switch on and off at the right time.
Appropriately timed bright light exposure can be used to modify out of phase sleep patterns so they become less erratic and more regular. Bright light in the morning (e.g. over breakfast) can advance your body clock, making you feel sleepy earlier. If the problem is interrupted sleep or waking too early, using a lightbox in the early evening can help to delay your sleep and wake times.