Aiding sleep Part three — circadian rhythm

There are two main chemical mediators which play a major role in our circadian rhythm, our body’s 24-hour internal clock, which controls our sleep-wake cycle; these are cortisol and melatonin. Setting our internal clock and sleep-wake cycle requires daylight exposure (and recognition of night), this regulates melatonin release. Equally, stress and increased cortisol levels will also affect our circadian rhythm.