First – what exactly is a circadian rhythm?
Your circadian rhythm is a 24-hour internal clock that runs in the background of your brain and cycles between sleepiness and alertness at regular intervals. It is also known as your sleep/wake cycle. Located in the suprachiasmatic nucleus (SCN) of the brain’s hypothalamus, this master clock receives light signals from the eye’s retina and sends information to other parts of the brain, keeping organs, tissues and hormones in sync.
Is everyone’s circadian rhythm the same?
Your sleep/wake cycle comes down to your genes, explains mindfulness and sleep psychologist Hope Bastine. “This would explain why some people are night owls while others are morning larks – this is known as your chronotype. For example, the ‘bear’ accounts for around 50% of the population – they wake up neither too early nor go to bed too late and tend to follow the natural light-dark cycle; the ‘lion’ wakes up early and makes up 15-20% of the population; the ‘wolf’ is late to rise and late to bed, are often creative and account for 15% of the population; while the ‘dolphin’ is a light sleeper and sensitive to noise, forming 10% of the population.”
What affects your body clock?
As Linda Geddes, author of Chasing The Sun, explains, it all comes down to the quality and quantity of light we are exposed to. “Until the 19th century, the only source of light at night came from candles and light, which was relatively dim and not very ‘blue’, unlike the light emitted by screens and lightbulbs. Today, we spend much of the day indoors, which is causing havoc with our body clock. Even on the gloomiest winter day, the outdoor light will be 25 times brighter than the average office.” As Linda explains, as our light exposure becomes similar during the day and night, our circadian rhythm flattens and becomes desynchronised.
How do you know if you’re out of sync?
The key signs include…
SLEEP: Problems falling or staying asleep, sleeping too much
WEIGHT: Weight gain, or an inability to lose weight
ENERGY: Low energy and a reliance on caffeine
DIET: Digestive problems, food cravings
MOOD: Depression, low mood and irrational anger
IMMUNITY: Frequent colds and illness, weak immune system
What does this mean for your health in the long-run?
As Hope explains, the consequences can be significant, with one study carried out on nurses – who are often subject to shift work – linking type 2 diabetes to the mismatch between chronotype and work schedule. Moreover, for the ‘wolf’ chronotype, work routines in direct conflict with their rhythm can wreak havoc with psychological wellbeing. Hope also says sleeping six hours or less per night has serious long-term health repercussions. “When we chronically rely on instant energy and sugary foods due to a lack of sleep, this is digging us into an early grave due to an increased risk of cardiovascular disorders, high blood pressure and diabetes,” she warns. Hope also references a separate study, which found one week of six-or-less hours of sleep per night alters 700 genes in the body, affecting cognitive function, emotional interpretation and overall behaviour.
How can you re-balance your body clock?
BE STRICT ABOUT BEDTIME: Having the same wake and bed time is crucial for encoding the brain and body to prepare you for sleep. “Try to reduce light exposure in the early evening, lower your room temperature, have a light dinner and exercise for at least 30 minutes a day, completed two to three hours before bedtime,” Hope recommends.
EAT LIKE YOUR ANCESTORS: “Irregular meal times can affect fat cells as well as the liver, gut and muscles. There’s also mounting evidence to suggest eating late at night causes weight gain, and puts you at greater risk of heart disease and diabetes. Try to match your meals with when your ancestors would have eaten, i.e. during the daytime with minimal food in the evening,” says Linda.
CLOCK THE CAFFEINE: Timing your caffeine consumption with your circadian clock is vital, advises Hope, especially as a late-in-the-day caffeinated beverage can inhibit melatonin production, meaning you’ll struggle to fall asleep. “Caffeine has a half-life of 5-7 hours, meaning you feel the immediate effects for up to seven hours, but it remains active in your system for up to 14 hours. Try to be mindful of when you are consuming caffeine, aiming to consume it when your cortisol levels naturally dip, ideally between 9-11:30am.”
SUPPLEMENT WITH MAGNESIUM: Around 15% of the population is deficient in magnesium so consider taking between 325-500mg before bed, as studies show it can improve sleep quality, especially for those with primary insomnia.
GET OUTSIDE: Linda is a big believer of getting exposure to light first thing in the morning, which triggers your brain to produce less melatonin. The minute your alarm goes off, open your curtains, and if you have time, go for a run or have your morning coffee outside.
DIM THE LIGHTS: Bright light keeps the brain awake. Make an effort to dim the lights two hours before bedtime and consider swapping your lightbulbs for a low-blue light variety.
Chasing The Sun: The New Science of Sunlight and How it Shapes Our Bodies and Minds by Linda Geddes is available on Amazon priced £7.50; for more information on Hope Bastine visit FreshPerception.com.
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