Since the invention of the light bulb in 1879 humans have been able to work longer & longer hours, not relying on the sun as the only source of light. Yes, candles were a thing but imagine trying to work long hours just by candlelight (that would suck). Thanks to Thomas Edison's invention the world is now more accessible & brighter than ever! But what if I told you this 24/7 illumination could be the very thing that is zapping your energy every day? Let me explain.
The Circadian Rhythm
You’ve probably heard of her, the balance between humankind and the environment. But what does this actually mean?
The circadian rhythm is a term that describes our behavioral & mental changes that occur over 24 hours. These changes over the day are coordinated by the release of neurotransmitters ( for example serotonin & norepinephrine during the day & melatonin at night) by the “master clock” located in the suprachiasmatic nucleus of the hypothalamus (1). This master clock is mostly influenced by the environmental light/dark cycle that occurs over the day but things like body temperature and eating/fasting cycles also affect it.
Some ways the Circadian Rhythm Affects You:
Impacts all aspects of metabolism (insulin sensitivity, inflammation, gut microbiota, obesity) through feeding/fasting cycles
Affects immune function
Manages hormone release
Regulates body temperature
Like I said this master clock is mostly influenced by the light/dark cycles of the environment so what happens if the darkness never comes (ie bright lights, smartphones, and tablets)?
As we know melatonin promotes sleep, melatonin concentrations go up when light fades, peak during complete darkness, and fall when exposed to light to help you wake up (2). This means if light is detected too close to bedtime (hello iPhone) melatonin production is disrupted leading to less circulating melatonin in your blood making it harder to fall and stay asleep. This lack of sleep & out of wack melatonin release disrupts the rest of the Circadian rhythm’s cues, causing a zap in energy & spiked stress hormones (ie cortisol). Conically spiked cortisol can lead to a lot of issues such as weight gain, high blood pressure, muscle weakness, & mood swings (anxiety, depression) just to name a few.
Why You Should Care
Yeah, yeah you’ve heard over and over that sleep is important and you need more of it but how much do you actually need and is it really a big deal if you miss an hour or 2 every night?
According to the American Sleep Association, adults need 7-8 hours of sleep every night, per the National Health Institute, the majority of Americans average only 6.7 hours of sleep each night. So what? 6.7 hours isn’t that far off from 7 how could so little time affect you?
Short sleep (less than 7 hours) has been linked to increased mortality, type 2 diabetes, hypertension, cardiovascular disease, coronary heart disease, and increased weight over the lifespan. Of note in 2019 the International Agency for Research on Cancer classified night shift work as a probable carcinogen in humans.
A study conducted by the New England Journal of Medicine found that there is a 24% increase in heart attacks on the Monday after the Spring time change (loss of an hr) compared to a 21% reduction in heart attacks the Tuesday after the fall time change (gain 1 hr)3. If this doesn’t make you rethink your sleep I don't know what will!
How to Support Your Circadian Rythem:
Wind down: 2-3 hrs before bed avoid bright lights. Dimming light & turning off screens helps melatonin production in the brain. Limiting light exposure at night has been shown to shorten the time it takes to fall asleep, improve sleep quality, and increase alertness in the morning (2).
8 hours in bed: try to go to bed at consistent times & spend 8 hrs in bed so you can get at least 7 hours of consistent sleep.
Ideally, wake up with the sun & go to sleep with the sun (~10 pm-6 am). Lack of sunshine triggers melatonin release & helps you fall asleep & sunlight in the morning helps you wake up.
Consistency is key: try to go to bed & wake up at the same times every day (within 15-30 minutes) even on weekends!
Get 30-60 minutes of sun each day. Even on a cloudy day daylight is the best way to resynchronize our brain clock (& get vitamin D!).
Exercise daily: any exercise is good but exercise in the afternoon/ early evening has been shown to be more efficient in helping control blood glucose levels compared to the same exercise in the morning (4).
Time-restricted eating: eat breakfast at consistent times of day, breakfast synchronizes the circadian rhythm for all other organs (5). Within the next 8-12 hours try to finish your meals. Fasting overnight for 12-16 hrs helps your body regulate circadian rhythm which in turn helps your body maintain weight, immune function, blood pressure, and glucose (this research is relatively new so more information is needed to fully understand this concept).
It can be hard to form new habits, especially around sleep but small changes add up! Implement what you can & don’t worry about the “perfect” routine because it doesn't exist! Great is the enemy of the good!
References:
Matenchuk BA, Mandhane PJ, Kozyrskyj AL. Sleep, circadian rhythm, and gut microbiota. Sleep Med Rev. 2020;53:101340. doi:10.1016/j.smrv.2020.101340
Vasey C, McBride J, Penta K. Circadian Rhythm Dysregulation and Restoration: The Role of Melatonin. Nutrients. 2021;13(10):3480. Published 2021 Sep 30. doi:10.3390/nu13103480
Sandhu A, Seth M, Gurm HS. Daylight savings time and myocardial infarction. Open Heart. 2014;1(1):e000019. Published 2014 Mar 28. doi:10.1136/openhrt-2013-000019
van der Velde JHPM, Boone SC, Winters-van Eekelen E, et al. Timing of physical activity in relation to liver fat content and insulin resistance. Diabetologia. 2023;66(3):461-471. doi:10.1007/s00125-022-05813-3
BaHammam AS, Pirzada A. Timing Matters: The Interplay between Early Mealtime, Circadian Rhythms, Gene Expression, Circadian Hormones, and Metabolism-A Narrative Review. Clocks Sleep. 2023;5(3):507-535. Published 2023 Sep 6. doi:10.3390/clockssleep5030034
Related Posts
