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your circadian rhythm and sleep

All you need to know about your body clock - and how to optimise it for health and sleep 🕒

▪️Our body systems ( in fact every single cell in our body) are controlled by an innate 24 hour clock, the circadian rhythm.

▪️It's mostly known for its effect on sleep, but the circadian rhythm has many other functions, controlling :

- digestion (releasing enzymes at usual meal times)

- hormone levels (ie energy levels, growth, insulin, cortisol)

- blood pressure

- physical strength

- appetite

- blood sugar and cholesterol levels

- immunity

- brain health

- cell and dna repair

▪️Disrupted circadian rhythms have far reaching effects, increasing the risk of disease and even reducing life expectancy (image credit john hopkins health)

▪️ These include higher risks of:

- type 2 diabetes

- some types of cancer

- poor immune function

- heart attacks and strokes

- dementia

- high blood pressure

- mental health problems

- obesity

▪️The circadian rhythm is controlled by a master clock in the brain called the suprachiasmatic nucleus (SCN) (4th pic)

▪️Clock genes in the SCN send out signals at different times of the day to regulate body functions

▪️The SCN is controlled by signals from the environment (ie light, food, activity, temperature etc)

▪️Our circadian rhythm makes us :

- sleepy at night (via melatonin, the sleep hormone)

- tired mid afternoon

- hungry at meal times

- warmer in the evening and cooler overnight

▪️Its also why we get jet lag changing time zones, why shift workers have higher risk of various health issues - and why teenagers are often night owls!

▪️So what's the best way to optimise circadian rhythm?

▪️Excerise outdoors in the morning - blue light levels are most intense then, and this sets the clock for the rest of the day. The SCN is particularly sensitive to blue light. This also helps regulate cortisol

▪️Keep your room cooler at night, to allow body temperature to drop (around 18-20 degrees is ideal)

▪️Avoid bright lights and screens 2h before bed (these suppress melatonin secretion)

▪️Avoid caffeine after 2pm, and alcohol within a few hours of bed

▪️Avoid vigorous excercise before bed, try some gentle stretching

▪️Practice time restricted eating (stop eating by 7pm at the latest, and aim to fast for ideally 14h overnight - this seems to be optimal for metabolism, weight, and blood sugars)

It's simple but so effective!!


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