Sleep and the circadian rhythm

The circadian rhythm is the body’s natural, 24 hour internal clock that regulates the sleep-wake cycle. It is triggered by cues from the environment, such as sunrise, sunset, movement and food intake, in order to optimize function in accordance with the time of day e.g feeling more energetic in the morning and more relaxed at night.

The circadian rhythm can be disrupted by modern lifestyle, which is less in sync with nature’s cues compared to historically. Stress, irregular work hours and eating patterns, irregular physical activity, lack of natural light in the day and exposure to artificial lighting after dark, disrupts this rhythm and makes it difficult to function at our best and sleep well.

Some ways to support the circadian rhythm to improve sleep include:

• Be in natural light within the first 30 minutes of waking – this will trigger the start of the daily rhythm that will cue alertness during the day and sleep at night

• Eat a protein-rich breakfast – this boosts blood sugar after the overnight fast (ideally at least a 12-hour gap since last eating). This provides the body with the energy it needs to use throughout day, to help feel sleepy at night

• Avoid snacking in the evening – ideally finish eating at least 3-4 hours before sleep, when digestion is functioning optimally, so the body can focus on rest and repair

• Movement – exercise promotes alertness, and exerts the energy needed to feel sleepy at night. Avoiding intense exercise in the evening/at night

• Avoid bright artificial light, including screens, late at night - dark cues the release of melatonin, the hormone that promotes sleep

• Manage stress and maintain a routine – stress can make us feel alert at irregular times. Developing a routine that promotes relaxation late in the day can help prompt sleep.