How light tells you when to sleep, focus and poo
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This is the next article in our ‘Light and health’ series, where we look at how light affects our physical and mental health in sometimes surprising ways. Read other articles in the series.
Exposure to light is crucial for our physical and mental health, as this and future articles in the series will show.
But the timing of that light exposure is also crucial. This tells our body to wake up in the morning, when to poo and the time of day to best focus or be alert. When we’re exposed to light also controls our body temperature, blood pressure and even chemical reactions in our body.
But how does our body know when it’s time to do all this? And what’s light got to do with it?
What is the body clock, actually?
One of the key roles of light is to re-set our body clock, also known as the circadian clock. This works like an internal oscillator, similar to an actual clock, ticking away as you read this article.
But rather than ticking you can hear, the body clock is a network of genes and proteins that regulate each other. This network sends signals to organs via hormones and the nervous system. These complex loops of interactions and communications have a rhythm of about 24 hours.
In fact, we don’t have one clock, we have trillions of body clocks throughout the body. The central clock is in the hypothalamus region of the brain, and each cell in every organ has its own. These clocks work in concert to help us adapt to the daily cycle of light and dark, aligning our body’s functions with the time of day.
However, our body clock is not precise and works to a rhythm of about 24 hours (24 hours 30 minutes on average). So every morning, the central clock needs to be reset, signalling the start of a new day. This is why light is so important.
The central clock is directly connected to light-sensing cells in our retinas (the back of the eye). This daily re-setting of the body clock with morning light is essential for ensuring our body works well, in sync with our environment.
In parallel, when we eat food also plays a role in re-setting the body clock, but this time the clock in organs other than the brain, such as the liver, kidneys or the gut.
So it’s easy to see how our daily routines are closely linked with our body clocks. And in turn, our body clocks shape how our body works at set times of the day.
What time of day?
Let’s take a closer look at sleep
The naturally occurring brain hormone melatonin is linked to our central clock and makes us feel sleepy at certain times of day. When it’s light, our body stops making melatonin (its production is inhibited) and we are alert. Closer to bedtime, the hormone is made, then secreted, making us feel drowsy.
Our sleep is also partly controlled by our genes, which are part of our central clock. These genes influence our chronotype – whether we are a “lark” (early riser), “night owl” (late sleeper) or a “dove” (somewhere in between).
But exposure to light at night when we are supposed to be sleeping can have harmful effects. Even dim light from light pollution can impair our heart rate and how we metabolise sugar (glucose), may lead to psychiatric disorders such as depression, anxiety and bipolar disorder, and increases the overall risk of premature death.
The main reason for these harmful effects is that light “at the wrong time” disturbs the body clock, and these effects are more pronounced for “night owls”.
This “misaligned” exposure to light is also connected to the detrimental health effects we often see in people who work night shifts, such as an increased risk of cancer, diabetes and heart disease.
How about the gut?
Digestion also follows a circadian rhythm. Muscles in the colon that help move waste are more active during the day and slow down at night.
The most significant increase in colon movement starts at 6.30am. This is one of the reasons why most people feel the urge to poo in the early morning rather than at night.
The gut’s day-night rhythm is a direct result of the action of the gut’s own clock and the central clock (which synchronises the gut with the rest of the body). It’s also influenced by when we eat.
How about focusing?
Our body clock also helps control our attention and alertness levels by changing how our brain functions at certain times of day. Attention and alertness levels improve in the afternoon and evening but dip during the night and early morning.
Those fluctuations impact performance and can lead to decreased productivity and an increased risk of errors and accidents during the less-alert hours.
So it’s important to perform certain tasks that require our attention at certain times of day. That includes driving. In fact, disruption of the circadian clock at the start of daylight savings – when our body hasn’t had a chance to adapt to the clocks changing – increases the risk of a car accident, particularly in the morning.
What else does our body clock control?
Our body clock influences many other aspects of our biology, including:
- physical performance by controlling the activity of our muscles
- blood pressure by controlling the system of hormones involved in regulating our blood volume and blood vessels
- body temperature by controlling our metabolism and our level of physical activity
- how our body handles drugs and toxins by controlling enzymes involved in how the liver and kidneys eliminate these substances from the body.
Morning light is important
But what does this all mean for us? Exposure to light, especially in the morning, is crucial for synchronising our circadian clock and bodily functions.
As well as setting us up for a good night’s sleep, increased morning light exposure benefits our mental health and reduces the risk of obesity. So boosting our exposure to morning light – for example, by going for a walk, or having breakfast outside – can directly benefit our mental and metabolic health.
However, there are other aspects about which we have less control, including the genes that control our body clock.
Frederic Gachon, Associate Professor, Physiology of Circadian Rhythms, Institute for Molecular Bioscience, The University of Queensland and Benjamin Weger, NHMRC Emerging Leadership Fellow Institute for Molecular Bioscience, The University of Queensland
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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Sugar, Hazelnuts, Books & Brains
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It’s Q&A Day!
Each Thursday, we respond to subscriber questions and requests! If it’s something small, we’ll answer it directly; if it’s something bigger, we’ll do a main feature in a follow-up day instead!
So, no question/request to big or small; they’ll just get sorted accordingly
Remember, you can always hit reply to any of our emails, or use the handy feedback widget at the bottom. We always look forward to hearing from you!
Q: Interesting info, however, I drink hazelnut milk LOL so would have liked a review of that. But now I want to give hemp and pea milks a try. Thanks
Aww! Here then just for you, is a quick rundown…
- Pros: high in protein¹, vitamin B, and vitamin E
- Cons: high in fat², low in calcium
¹Compared head-to-head with almond milk for example, it has double the protein (but also double the calories)
²However, is also has been found to lower LDL (bad) cholesterol (and incidentally, also reduce inflammation), and in a later systematic review, it was found to not correlate to weight gain, despite its high calorie-content.
If you don’t already, and would like to try making your own…
Click here for step-by-step instructions to make your own hazelnut milk! (very simple)
Q: Wondering if you can evaluate CLA and using it to assist with weight loss. Thanks
Will do! (Watch this space)
Q: What’s the process behind the books you recommend? You seem to have a limitless stream of recommendations
We do our best!
The books we recommend are books that…
- are on Amazon—it makes things tidy, consistent, and accessible. And if you end up buying one of the books, we get a small affiliate commission*.
- we have read—we would say “obviously”, but you might be surprised how many people write about books without having read them.
- pertain in at least large part to health and/or productivity.
- are written by humans—bookish people (and especially Kindle Unlimited users) may have noticed lately that there are a lot of low quality AI-written books flooding the market, sometimes with paid 5-star reviews to bolster them. It’s frustrating, but we can tell the difference and screen those out.
- are of a certain level of quality. They don’t have to be “top 5 desert-island books”, because well, there’s one every day and the days keep coming. But they do have to genuinely deliver the value that we describe, and merit a sincere recommendation.
- are varied—we try to not give a run of “samey” books one after another. We will sometimes review a book that covers a topic another previously-reviewed book did, but it must have something about it that makes it different. It may be a different angle or a different writing style, but it needs something to set it apart.
*this is from Amazon and isn’t product-specific, so this is not affecting our choice of what books to review at all—just that they will be books that are available on Amazon.
Q: Great video on dopamine. Thumbs up on the book recommendation. Would you please consider doing a piece or two on inflammation? I live with Lupus and it is a constant struggle. Thanks for the awesome work you do. Have an excellent day.
Great suggestion! We will do that, and thank you for the kind words!
Q: Why is your newsletter called 10almonds? Maybe I missed it in the intro email, but my curiosity wants to know the significance. Thanks!”
It’s a reference to a viral Facebook hoax! There was a post going around that claimed:
❝HEADACHE REMEDY. Eat 10–12 almonds, the equivalent of two aspirins, next time you have a headache❞ ← not true!
It made us think about how much health-related disinformation there was online… So, calling ourselves 10almonds was a bit of a tongue-in-cheek reference to that story… but also a reminder to ourselves:
We must always publish information with good scientific evidence behind it!
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An unbroken night’s sleep is a myth. Here’s what good sleep looks like
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What do you imagine a good night’s sleep to be?
Often when people come into our sleep clinic seeking treatment, they share ideas about healthy sleep.
Many think when their head hits the pillow, they should fall into a deep and restorative sleep, and emerge after about eight hours feeling refreshed. They’re in good company – many Australians hold the same belief.
In reality, healthy sleep is cyclic across the night, as you move in and out of the different stages of sleep, often waking up several times. Some people remember one or more of these awakenings, others do not. Let’s consider what a healthy night’s sleep looks like.
Bricolage/Shutterstock Sleep cycles are a roller-coaster
As an adult, our sleep moves through different cycles and brief awakenings during the night. Sleep cycles last roughly 90 minutes each.
We typically start the night with lighter sleep, before moving into deeper sleep stages, and rising again into rapid eye movement (REM) sleep – the stage of sleep often linked to vivid dreaming.
If sleeping well, we get most of our deep sleep in the first half of the night, with REM sleep more common in the second half of the night.
Deepest sleep usually happens during the first half of the night. Verin/Shutterstock Adults usually move through five or six sleep cycles in a night, and it is entirely normal to wake up briefly at the end of each one. That means we might be waking up five times during the night. This can increase with older age and still be healthy. If you’re not remembering these awakenings that’s OK – they can be quite brief.
What does getting a ‘good’ sleep actually mean?
You’ll often hear that adults need between seven and nine hours of sleep per night. But good sleep is about more than the number of hours – it’s also about the quality.
For most people, sleeping well means being able to fall asleep soon after getting into bed (within around 30 minutes), sleeping without waking up for long periods, and waking feeling rested and ready for the day.
You shouldn’t be feeling excessively sleepy during the day, especially if you’re regularly getting at least seven hours of refreshing sleep a night (this is a rough rule of thumb).
But are you noticing you’re feeling physically tired, needing to nap regularly and still not feeling refreshed? It may be worthwhile touching base with your general practitioner, as there a range of possible reasons.
Common issues
Sleep disorders are common. Up to 25% of adults have insomnia, a sleep disorder where it may be hard to fall or stay asleep, or you may wake earlier in the morning than you’d like.
Rates of common sleep disorders such as insomnia and sleep apnoea – where your breathing can partially or completely stop many times during the night – also increase with age, affecting 20% of early adults and 40% of people in middle age. There are effective treatments, so asking for help is important.
Beyond sleep disorders, our sleep can also be disrupted by chronic health conditions – such as pain – and by certain medications.
There can also be other reasons we’re not sleeping well. Some of us are woken by children, pets or traffic noise during the night. These “forced awakenings” mean we may find it harder to get up in the morning, take longer to leave bed and feel less satisfied with our sleep. For some people, night awakenings may have no clear cause.
A good way to tell if these awakenings are a problem for you is by thinking about how they affect you. When they cause feelings of frustration or worry, or are impacting how we feel and function during the day, it might be a sign to seek some help.
If waking up in the night is interfering with your normal day-to-day activities, it may indicate a problem. BearFotos/Shutterstock We also may struggle to get up in the morning. This could be for a range of reasons, including not sleeping long enough, going to bed or waking up at irregular times – or even your own internal clock, which can influence the time your body prefers to sleep.
If you’re regularly struggling to get up for work or family needs, it can be an indication you may need to seek help. Some of these factors can be explored with a sleep psychologist if they are causing concern.
Can my smart watch help?
It is important to remember sleep-tracking devices can vary in accuracy for looking at the different sleep stages. While they can give a rough estimate, they are not a perfect measure.
In-laboratory polysomnography, or PSG, is the best standard measure to examine your sleep stages. A PSG examines breathing, oxygen saturation, brain waves and heart rate during sleep.
Rather than closely examining nightly data (including sleep stages) from a sleep tracker, it may be more helpful to look at the patterns of your sleep (bed and wake times) over time.
Understanding your sleep patterns may help identify and adjust behaviours that negatively impact your sleep, such as your bedtime routine and sleeping environment.
And if you find viewing your sleep data is making you feel worried about your sleep, this may not be useful for you. Most importantly, if you are concerned it is important to discuss it with your GP who can refer you to the appropriate specialist sleep health provider.
Amy Reynolds, Associate Professor in Clinical Sleep Health, Flinders University; Claire Dunbar, Research Associate, Sleep Health, Flinders University; Gorica Micic, Postdoctoral Research Fellow, Clinical Psychologist, Flinders University; Hannah Scott, Research Fellow in Sleep Health, Flinders University, and Nicole Lovato, Associate Professor, Adelaide Institute for Sleep Health, Flinders University
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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PCOS Repair Protocol – by Tamika Woods
10almonds is reader-supported. We may, at no cost to you, receive a portion of sales if you purchase a product through a link in this article.
PCOS (Polycystic Ovary Syndrome) affects about 1 in 5 women, and the general position of the medical establishment is “Oh dear, how sad; never mind”.
…which leaves a lot of people suffering with symptoms with little to no help.
This book looks to address that, and while it doesn’t claim to cure PCOS, it offers a system for managing (including: reducing) the symptoms. The author, a clinical nutritionist by academic background, tackles this in large part via being mindful about what one eats, in the context of the gut and endocrine system specifically.
It’s not just “have a gut healthy diet and eat foods with these nutrients”, though (although yes: also that). Rather, the author walks us through in-depth quizzes and lab testing advice, to advise the reader on how to understand the root cause of your PCOS symptoms, and then address each of those with an individualized management plan.
The style is on the low-end of pop-science, notwithstanding the clinically-informed content. For those who like a very chatty informal approach, you’ll find this one perfect. For those who don’t, well, you won’t find this one perfect, but you will most likely find it informative all the same.
Bottom line: if you or someone you care about (do you know 5 women?) has PCOS, the information in here could make a difference.
Click here to check out PCOS Repair Protocol, and suffer less!
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Pear vs Prickly Pear – Which is Healthier?
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Our Verdict
When comparing pear to prickly pear, we picked the prickly.
Why?
Both of these fruits are fine and worthy choices, but the prickly pear wins out in nutritional density.
Looking at the macros to start with, the prickly pear is higher in fiber and lower in carbs, resulting in a much lower glycemic index. However, non-prickly pears are already low GI, so this is not a huge matter. Whether it’s pear’s GI of 38 or prickly pear’s GI of 7, you’re unlikely to experience a glucose spike.
In the category of vitamins, pear has a little more of vitamins B5, B9, E, K, and choline, but the margins are tiny. On the other hand, prickly pear has more of vitamins A, B1, B2, B3, B6, and C, with much larger margins of difference (except vitamin B1; that’s still quite close). Even before taking margins of difference into account, this is a slight win for prickly pear.
When it comes to minerals, things are more pronounced; pear has more manganese, while prickly pear has more calcium, iron, magnesium, phosphorus, potassium, selenium, and zinc.
In short, both pears are great (so do enjoy the pair), but prickly pear is the clear winner where one must be declared.
Want to learn more?
You might like to read:
Apple vs Pear – Which is Healthier?
Take care!
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Ghanaian Red Bean & Sweet Potato Groundnut Stew
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This is a dish popular in principle throughout West Africa. We say “in principle” because that’s a big place, and there is a lot of regional variation. The archetypal peanut stew is from Senegal (as maafe) or Mali (as tigadèguèna), but for its more balanced nutritional profile we’ve chosen one from Ghana—and since there are regional variations within Ghana too, we should specify that this one is from the south.
If you are allergic to nuts, you can substitute a seed butter (or tahini) for the nut butter, and omit the nuts—this will work in culinary terms and be fine healthwise, but we can’t claim it would be the same dish, having lost its defining ingredient. If your allergy is solely to peanuts, then substituting with any oily nut would work. So, not almonds for example, but cashews or even walnuts would be fine.
You will need
- 1½ lbs sweet potatoes, peeled and cut into ½” cubes
- 2 cups low-sodium vegetable stock
- 2 cans kidney beans, drained, cooked, and rinsed (or 2 cups same; cooked, drained, and rinsed)
- 1 can chopped tomatoes
- ½ cup unsalted dry-roasted peanuts
- 1 onion, chopped
- 1 red bell pepper, deseeded and chopped
- ¼ bulb garlic, finely chopped
- 2 heaped tbsp unsalted peanut butter, minimal (ideally: no) additives
- 2 tsp white miso paste
- 2 tsp grated fresh ginger
- 1 tsp ground cumin
- 1 tsp cayenne pepper
- 1 tsp black pepper
- ½ tsp MSG or 1 tsp low-sodium salt
- ½ tsp coarsely ground nigella seeds
- Extra virgin olive oil
Method
(we suggest you read everything at least once before doing anything)
1) Heat some oil in a sauté pan, or other pan suitable for both frying and fitting the entire stew in. Fry the onions until softened, turn the heat down low, and add the garlic, ginger, red bell pepper, cumin, cayenne, black pepper, and MSG/salt.
2) Add ¼ cup of the vegetable stock, and the sweet potato, and turn the heat back up, on high for about 30 seconds to get it to temperature, and then take it down to a simmer.
3) Stir in the miso paste and chopped tomatoes.
4) Add most of the rest of the vegetable stock, keeping ¼ cup aside. Simmer for about 20 minutes.
5) Stir in the kidney beans, and simmer for about 30 minutes more—the sweet potato should be soft now; if it isn’t, let it simmer a while longer until it is.
6) Combine the peanut butter with the remaining ¼ cup vegetable stock, and blend until smooth. Stir it into the stew.
7) If the stew is looking more like a soup than a stew, take out 1 cup and blend this 1 cup to a purée, adding it back in.
8) Add half the peanuts unto the stew. Taste, and adjust the seasonings if necessary.
9) Crush the remaining peanuts using a pestle and mortar; not too much though; you want them broken into bits, not pulverised.
10) Garnish with the crushed nuts and nigella seeds, and serve.
Enjoy!
Want to learn more?
For those interested in some of the science of what we have going on today:
- Eat More (Of This) For Lower Blood Pressure
- Lycopene’s Benefits For The Gut, Heart, Brain, & More
- Our Top 5 Spices: How Much Is Enough For Benefits? ← we used 4/5 today!
Take care!
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Sensitive – by Jenn Granneman and Andre Sólo
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This book is written for what is called the “Highly Sensitive Person”, which makes it sound like a very rare snowflake condition, when in fact the diagnostic criteria (discussed early in the book) yield a population bell curve of 30:40:30, whereupon 30% are in the band of “high sensitivity”, 40% “normal sensitivity” and the remainder “low sensitivity”. You may note that “high” and “low” together outnumber “normal”, but statistics is like that.
So, if you’re one of the approximately one in three people who fall into the higher category, and/or you have a loved one who is in that category, then this book looks at the many advantages to a commonly stigmatized and (by cruel irony) criticized personality trait.
Those advantages range from personal life to work and even public life (yes, really), and can be grown, positively highlighted, used, and enjoyed.
In the category of criticism, the book does not usefully cover the benefit of psychological resilience. Resilience does not mean losing sensitivity, just, being able to also dry one’s tears and weather life’s slings and arrows when the world is harsher than one might like. But for the authors, they have stacked all their chips on “we must make the world a better place”. Which is a noble goal, if not always an immediately attainable one.
Bottom line: if you are more sensitive than average and would like to use that to benefit yourself and those around you, then this is the book for you!
Click here to check out Sensitive, and make the most of your strengths!
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