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How does circadian rhythm affect your sleep?

Circadian rhythm are 24h cycles which are the part of our internal body clock and help to regulate essential functions and processes within the body. One of the most important circadian rhythm is the wake-sleep cycle. When circadian rhythm is consistent it promotes restorative sleep, however when it is out of balance it can trigger significant sleeping problems such as insomnia, depression and inability to lose weight.

Research suggests that circadian rhythm has a significant effect on our physical and mental health. Circadian rhythms coordinate mental and physical systems throughout the body. The digestive system produces proteins to satisfy typical timing of meals and the endocrine system regulates the hormones to support energy regulation.

The circadian rhythm is connected to the master clock in the brain, specifically, in the suprachiasmatic nucleus (SCN), which is in a part of the brain called the hypothalamus. At different times of the day, clock genes in the SCN send signals to regulate activity throughout the body.

Magdalena Marvell is a Nutritional Practitioner and Founder of the Persea Clinic which helps support clients who want to optimise their health in areas such as gut health, hormonal balance, skin conditions, weight management, family nutrition. To find out more about her work please visit

The SCN is highly sensitive to light, which affects how the SCN coordinates internal clocks within the body. Therefore circadian rhythms are closely impacted by day and night1.

During the day, light exposure causes our master clock to send signals that generate alertness and help keep us awake and active. During the night our master clock stimulates the production of melatonin (hormone which promotes sleep), and then keeps transmitting signals to keep us asleep throughout the night.

In this way, our circadian rhythm aligns our sleep and wakefulness with day and night to create a stable cycle of restorative rest that enables increased daytime activity.

Circadian rhythms can influence our metabolism and weight through the management of blood sugar and cholesterol. It also affects the immune system and well as the process of DNA repair involved in the prevention of cancer.
When the sleep-wake circadian rhythm is disturbed, our body’s system fails to function efficiently.

Without sufficient signalling from the internal clock, a person can struggle to fall asleep, wake during the night, or be unable to sleep longer in the morning.

The total sleep duration can be reduced, and a disrupted circadian rhythm can trigger lower quality and less deep sleep.

What can disturb our circadian rhythm?
Circadian rhythm can be disturbed either over the short or long period of time. There are a number of types of circadian rhythm sleep-wake disorders which have been identified by researchers.

There are diverse causes of circadian rhythm disorders. Some circadian disruptions can be linked to an individuals behaviour (travel or work), that interferes with sleep schedules and daylight exposure. Other disorders can be related to an underlying issue such as genetic factors which causes an inability to receive or process environmental signals that regulate the body’s master clock2.

The main include: jet lag, shift work where it is required to sleep during the day and stay awake at night, advanced sleep phase disorder where people get very tired in the evening and wake very early in the morning, delayed sleep phase disorder this type of circadian rhythm disruption is associated with “night owls” who stay up late at night and sleep in late in the morning. It is rare among the general population (affecting just 1 or 2 people out of every 1,000) but impacts up to 16% of teenagers; Non-24 Hour Sleep Wake Disorder this condition appears mainly in people who are blind and are not able to receive the light based cues to support the circadian rhythm.

Irregular Sleep-Wake Rhythm Disorder – people with this rare disorder don’t have a regular pattern to their sleep and may compensate with many naps throughout a 24-hour day. It is frequently connected to conditions such as dementia or brain injury which impacts the proper functioning of the master clock in the hypothalamus.

How to improve the sleep-wake cycle?
Maintaining sleep hygiene every night can be an important step to support your healthy circadian rhythm.
Expose yourself to natural light especially earlier in the morning. This may help to strengthen the circadian signals.

Go to bed around the same time every night. Varying your bedtime or morning wake-up time can inhibit your body’s ability to adjust to a regular circadian rhythm.

Stay active. Exercising during the day can help your internal clock and make it easier to soundly fall asleep at night.
Limit light and electronic devices before going to bed. Exposure to blue light or artificial light can interfere with circadian rhythm. Dim the lights and keep electronic devices away from your bed.

Nap early in the afternoon and keep them short. Late naps can push back your bedtime and interfere with your regular sleep schedule.



Healthy recipes with Magdalena – Lemon balm pesto
Lemon balm is known form its calming properties and it has been reported to help with sleep related disorders such as insomnia. It is commonly consumed as tea but it can also be used in pesto. Here is the simple recipe for your bedtime snack!

• Fresh lemon balm leaves
• Parmesan or Pecorino Romano – I use whatever I have at the time, both versions are suitable
• Almonds – raw, whole almonds or pine nuts
• Olive oil – make sure to use a mild oil otherwise the pesto becomes bitter
• Lemon juice – freshly squeezed
• Garlic – about 5 medium cloves for one batch
• Salt and pepper to season

How to make it:

  1. Wash the lemon balm well. Pat it with kitchen towel to dry.
  2. Remove the leaves from the stems. 3. Chop them roughly and place them in a food processor. Process to a rough paste.
  3. Add the remaining ingredients: cut cheese, whole almonds/pine nuts, chopped garlic, lemon juice, salt, pepper, and olive oil.
  4. Mix everything in the food processor to obtain a smooth paste. Scrape the walls of the food processor a few times in between.
  5. Transfer the pesto into small dish. Keep it in the fridge for up to 2 weeks (pour over a little oil to keep it fresh).
  6. Enjoy as your bedtime snack with some savoury oatcakes!


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