How light tells you when to sleep, focus and poo
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.
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.
Don’t Forget…
Did you arrive here from our newsletter? Don’t forget to return to the email to continue learning!
Recommended
Learn to Age Gracefully
Join the 98k+ American women taking control of their health & aging with our 100% free (and fun!) daily emails:
-
Are You A Calorie-Burning Machine?
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.
Burn, Calorie, Burn
In Tuesday’s newsletter, we asked you whether you count calories, and got the above-depicted, below-described set of answers:
- About 56% said “I am somewhat mindful of calories but keep only a rough tally”
- About 32% said “I do not count calories / I don’t think it’s important for my health”
- About 13% said “I rigorously check and record the calories of everything I consume”
So what does the science say, about the merits of all these positions?
A food’s calorie count is a good measure of how much energy we will, upon consuming the food, have to use or store: True or False?
False, broadly. It can be, at best, a rough guideline. Do you know what a calorie actually is, by the way? Most people don’t.
One thing to know before we get to that: there’s “cal” vs “kcal”. The latter is generally used when it comes to foodstuffs, and it’s what we’ll be meaning whenever we say “calorie” here. 1cal is 1/1000th of a kcal, that’s all.
Now, for what a calorie actually is:
A calorie is the amount of energy needed to raise the temperature of 1 liter of water by 1℃
Question: so, how to we measure how much food is needed to do that?
Answer: by using a bomb calorimeter! Which is the exciting name for the apparatus used to literally burn food and capture the heat produced to indeed raise the temperature of 1 liter of water by 1℃.
If you’re having trouble imagining such equipment, here it is:
Bomb Calorimeter: Definition, Construction, & Operation (with diagram and FAQs)
The unfortunate implication of the above information
A kilogram of sawdust contains about a 1000 kcal, give or take what wood was used and various other conditions.
However, that does not mean you can usefully eat the sawdust. In other words:
Calorie count tells us only how good something is at raising the temperature of water if physically burned.
Now do you see why oils and sugars have such comparably high calorie counts?
And while we may talk about “burning calories” as a metaphor, we do not, in fact, have a little wood stove inside us burning the food we eat.
A calorie is a calorie: True or False?
Definitely False! Building on from the above… We will get very little energy from sawdust; it’s not just that we can’t use it; we can’t store it either; it’ll mostly pass through as fiber.
(however, please do not use sawdust to get your daily dose of fiber either, as it is not safe for human consumption and may give you diseases, depending on what is lurking in it)
But let’s look at oil and sugar, two very high-calorie categories of food, because they’re really easy to physically burn and they give off a good flame.
A bomb calorimeter may treat them quite equally, but to our body, they are metabolically very different indeed.
For a start, most sugars will get absorbed and processed much more quickly than most oils, and that can overwhelm the liver (responsible for glycogen management), and lead to non-alcoholic fatty liver disease, diabetes, and more. Metabolic syndrome in general, and if you keep it up too much and you may find it’s now a lottery between dying of NAFLD, diabetes, or heart disease (it’ll usually be the heart disease that kills).
See also:
- Which Sugars Are Healthier, And Which Are Just The Same?
- 10 Ways To Balance Blood Sugars
- How To Unfatty A Fatty Liver
Meanwhile, we know all about the different kinds of nutritional profiles that oils can have, and some can promote having high energy without putting on fat, while others can strain the heart. Not even “a fat is a fat”, so “a calorie is a calorie” doesn’t get much mileage outside of a bomb calorimeter!
See also:
A calorie-controlled / calorie-restricted diet is an effective weight loss strategy: True or False?
True, usually! Surprise!
- On the one hand: calories are a wildly imprecise way to reckon the value of food, and using them as a guide to health can be dangerously misleading
- On the other hand: the very activity of calorie-counting itself promotes mindful eating, which is very good for the health
There is a strong difference between the mind of somebody who is carefully logging their pre-bedtime piece of chocolate and reflecting on its nutritional value, vs someone who isn’t sure whether this is their second or third glass of wine, nor how much the glass contained.
So if you want to get most of the benefits of a calorie-controlled diet without counting calories, you may try taking a “mindful eating” approach to diet.
However! If you want to do this for weight loss, be aware, that you will have to practice it all the time, not just for one meal here and there.
You can read more on how to do “mindful eating” here:
Dr. Rupy Aujla: The Kitchen Doctor | Mindful Eating & Interoception
Take care!
Share This Post
-
Stay off My Operating Table – by Dr. Philip Ovadia
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.
With heart disease as the #1 killer worldwide, and 88% of adults being metabolically unhealthy (leading cause of heart disease), this is serious!
Rather than taking a “quick fix” advise-and-go approach, Dr. Ovadia puts the knowledge and tools in our hands to do better in the long term.
As a heart surgeon himself, his motto here is:
❝What foods to put on your table so you don’t end up on mine❞
There’s a lot more to this book than the simple “eat the Mediterranean diet”:
- While the Mediterranean diet is generally considered the top choice for heart health, he also advises on how to eat healthily on all manner of diets… Carnivore, Keto, Paleo, Atkins, Gluten-Free, Vegan, you-name-it.
- A lot of the book is given to clearing up common misconceptions, things that sounded plausible but are just plain dangerous. This information alone is worth the price of the book, we think.
- There’s also a section given over to explaining the markers of metabolic health, so you can monitor yourself effectively
- Rather than one-size-fits-all, he also talks about common health conditions and medications that may change what you need to be doing
- He also offers advice about navigating the health system to get what you need—including dealing with unhelpful doctors!
Bottom line: A very comprehensive (yet readable!) manual of heart health.
Get your copy of Stay Off My Operating Table from Amazon today!
Share This Post
-
Heal & Reenergize Your Brain With Optimized Sleep Cycles
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.
Sometimes 8 hours sleep can result in grogginess while 6 hours can result in waking up fresh as a daisy, so what gives? Dr. Tracey Marks explains, in this short video.
Getting more than Zs in
Sleep involves 90-minute cycles, usually in 4 stages:
- Stage 1: (drowsy state): brief muscle jerks; lasts a few minutes.
- Stage 2: (light sleep): sleep spindles for memory consolidation; 50% of total sleep.
- Stage 3 (deep sleep): tissue repair, immune support, brain toxin removal via the glymphatic system.
- Stage 4 (REM sleep): emotional processing, creativity, problem-solving, and dreaming.
Some things can disrupt some or all of those. To give a few common examples:
- Alcohol: impairs REM sleep.
- Caffeine: hinders deep sleep even if consumed hours before bed.
- Screentime: delays sleep onset due to blue light (but not by much); the greater problem is that it can also disrupt REM sleep due to mental stimulation.
To optimize things, Dr. Marks recommends:
- 90-minute rule: plan sleep to align with full cycles (e.g: 22:30 to 06:00 = 7½ hours, which is 5x 90-minute cycles).
- Smart alarms: use sleep-tracking apps with built-in alarm, to wake you up during light sleep phases.
- Strategic naps: keep naps to 20 minutes or a full 90-minute cycle.
- Pink noise: improves deep sleep.
- Meal timing: avoid eating within 3 hours of bedtime.
- Natural light: get morning light exposure in the morning to strengthen circadian rhythm.
For more on all of this, enjoy:
Click Here If The Embedded Video Doesn’t Load Automatically!
Want to learn more?
You might also like to read:
Calculate (And Enjoy) The Perfect Night’s Sleep
Take care!
Share This Post
Related Posts
-
Aging Is Inevitable… Or is it?
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.
Aging is inevitable… Or is it?
We’ve talked before about how and why aging happens. We’ve also talked about the work to tackle aging as basically an engineering problem, with the premise that our bodies are biological machines, and machines can be repaired. We also recommended a great book about this, by the way. But that’s about interfering with the biological process of aging. What about if the damage is already done?
“When the damage is done, it’s done”
We can do a lot to try to protect ourselves from aging, and we might be able to slow down the clock, but we can’t stop it, and we certainly can’t reverse it… right?
Wrong! Or at least, so we currently understand, in some respects. Supplementation with phosphatidylserine, for example, has shown promise for not just preventing, but treating, neurodegeneration (such as that caused by Alzheimer’s disease). It’s not a magic bullet and so far the science is at “probably” and “this shows great promise for…” and “this appears to…”
Phosphatidylserene does help slow neurodegeneration
…because of its role in allowing your cells to know whether they have permission to die.
This may seem a flippant way of putting it, but it’s basically how cell death works. Cells do need to die (if they don’t, that’s called cancer) and be replaced with new copies, and those copies need to be made before too much damage is accumulated (otherwise the damage is compounded with each new iteration). So an early cell death-and-replacement is generally better for your overall health than a later one.
However, neurons are tricky to replace, so phosphatidylserine effectively says “not you, hold on” to keep the rate of neuronal cell death nearer to the (slow) rate at which they can be replaced.
One more myth to bust…
For the longest time we thought that adults, especially older adults, couldn’t make new brain cells at all, that we grew a certain number, then had to hang onto them until we died… suffering diminished cognitive ability with age, on account of losing brain cells along the way.
It’s partly true: it’s definitely easier to kill brain cells than to grow them… Mind you, that’s technically true of people, too, yet the population continues to boom!
Anyway, new research showing that adults do, in fact, grow new braincells was briefly challenged by a 2018 study that declared: Human hippocampal neurogenesis drops sharply in children to undetectable levels in adults after all, never mind, go back to your business.
So was adult neurogenesis just a myth to be busted after all? Nope.
It turned out, the 2018 study had a methodological flaw!
To put it in lay terms: they had accidentally melted the evidence.
A 2019 study overcame this flaw by using a shorter fixation time for the cell samples they wanted to look at, and found that there were tens of thousands of “baby neurons” (again with the lay terms), newly-made brain cells, in samples from adults ranging from 43 to 87.
Now, there was still a difference: the samples from the youngest adult had 30% more newly-made braincells than the 87-year-old, but given that previous science thought brain cell generation stopped in childhood, the fact that an 87-year-old was generating new brain cells 30% less quickly than a 43-year-old is hardly much of a criticism!
As an aside: samples from patients with Alzheimer’s also had a 30% reduction in new braincell generation, compared to samples from patients of the same age without Alzheimer’s. But again… Even patients with Alzheimer’s were still growing some new brain cells.
Read it for yourself: Adult hippocampal neurogenesis is abundant in neurologically healthy subjects and drops sharply in patients with Alzheimer’s disease
In a nutshell…
- We can’t fully hit pause on aging just yet, but we can definitely genuinely slow it
- We can also, in some very specific ways, reverse it
- We can slow the loss of brain cells
- We can grow new brain cells
- We can reduce our risk of Alzheimer’s, and at least somewhat mitigate it if it appears
- We know that phosphatidylserine supplementation may help with most (if not all) of the above
- We don’t sell that (or anything else) but for your convenience, here it is on Amazon if you’re interested
Don’t Forget…
Did you arrive here from our newsletter? Don’t forget to return to the email to continue learning!
Learn to Age Gracefully
Join the 98k+ American women taking control of their health & aging with our 100% free (and fun!) daily emails:
-
Why Everyone You Don’t Like Is A Narcissist
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.
We’ve written before about how psychiatry tends to name disorders after how they affect other people, rather than how they affect the bearer, and this is most exemplified when it comes to personality disorders. For example:
“You have a deep insecurity about never being good enough, and you constantly mess up in your attempt to overcompensate? You may have Evil Bastard Disorder!”
“You have a crippling fear of abandonment and that you are fundamentally unloveable, so you do all you can to try to keep people close? You must have Manipulative Bitch Disorder!”
See also: Miss Diagnosis: Anxiety, ADHD, & Women
Antisocial DiagnosesThese days, it is easy to find on YouTube countless videos of how to spot a narcissist, with a list of key traits that all mysteriously describe exactly the exes of everyone in the comments.
And these days it is mostly “narcissist”, because “psychopath” and “sociopath” have fallen out of popular favor a bit:
- perhaps for coming across as overly sensationalized, and thus lacking credibility
- perhaps because “Narcissistic Personality Disorder (NPD)” exists in the DSM-5 (the US’s latest “Diagnostic and Statistical Manual of Mental Disorders”), while psychopathy and sociopathy are not mentioned as existing.
You may be wondering: what do “psychopathy” and “sociopathy” mean?
And the answer is: they mean whatever the speaker wants them to mean. Their definitions and differences/similarities have been vigorously debated by clinicians and lay enthusiasts alike for long enough that the scientific world has pretty much given up on them and moved on.
Stigma vs pathology
Because of the popular media (and social media) representation of NPD, it is easy to armchair diagnose one’s relative/ex/neighbor/in-law/boss/etc as being a narcissist, because the focus is on “narcissists do these bad things that are mean to people”.
If the focus were instead on “narcissists have cripplingly low self-esteem, and are desperate to not show weakness in a world they have learned is harsh and predatory”, then there may not be so many armchair diagnoses—or at the very least, the labels may be attached with a little more compassion, the same way we might with other mental health issues such as depression.
Not that those with depression get an easy time of it socially either—society’s response is generally some manner of “aren’t you better yet, stop being lazy”—but at the very least, depressed people are not typically viewed with hatred.
A quick aside: if you or someone you know is struggling with depression, here are some things that actually help:
The Mental Health First-Aid You’ll Hopefully Never Need
The disorder is not the problem
Maybe your relative, ex, neighbor, etc really is clinically diagnosable as a narcissist. There are still two important things to bear in mind:
- After centuries of diagnosing people with mental health maladies that we now know don’t exist per se (madness, hysteria, etc), and in recent decades countless revisions to the DSM and similar tomes, thank goodness we now have the final and perfect set of definitions that surely won’t be re-written in the next few years or so ← this is irony; it will absolutely be re-written numerous times yet because of course it’s still not a magically perfect descriptor of the broad spectrum of human nature
- The disorder is not the problem; the way they treat (or have treated) you is the problem.
For example, let’s take a key thing generally attributed to narcissists: a lack of empathy
Now, empathy can be divided into:
- affective empathy: the ability to feel what other people are feeling
- cognitive empathy: the ability to intellectually understand what other people are feeling (akin to sympathy, which is the same but with the requisite of having experienced the thing in question oneself)
A narcissist (as well as various other people without NPD) will typically have negligible affective empathy, and their cognitive empathy may be a little sluggish too.
Sluggish = it may take them a beat longer than most people, to realize what an external signifier of emotions means, or correctly guess how something will be felt by others. This can result in gravely misspeaking (or inappropriately emoting), after failing to adequately quickly “read the room” in terms of what would be a socially appropriate response. To save face, they may then either deny/minimize the thing they just said/did, or double-down on it and go on [what for them feels like] the counterattack.
As to why this shutting off of empathy happens: they have learned that the world is painful, and that people are sources of pain, and so—to avoid further pain—have closed themselves off to that, often at a very early age. This will also apply to themselves; narcissists typically have negligible self-empathy too, which is why they will commonly make self-destructive decisions, even while trying to put themselves first.
Important note on how this impacts other people: the “Golden Rule” of “treat others as you would wish to be treated” becomes intangible, as they have no more knowledge of their own emotional needs than they do of anyone else’s, so cannot make that comparison.
Consider: if instead of being blind to empathy, they were colorblind… You would probably not berate them for buying green apples when you asked for red. They were simply incapable of seeing that, and consequently made a mistake. So it is when it’s a part of the brain that’s not working normally.
So… Since the behavior does adversely affect other people, what can be done about it? Even if “hate them for it and call for their eradication from the face of the Earth” is not a reasonable (or compassionate) option, what is?
Take the bull by the horns
Above all, and despite all appearances, a narcissist’s deepest desire is simply to be accepted as good enough. If you throw them a life-ring in that regard, they will generally take it.
So, communicate (gently, because a perceived attack will trigger defensiveness instead, and possibly a counterattack, neither of which are useful to anyone) what behavior is causing a problem and why, and ask them to do an alternative thing instead.
And, this is important, the alternative thing has to be something they are capable of doing. Not merely something that you feel they should be capable of doing, but that they are actually capable of doing.
- So not: “be a bit more sensitive!” because that is like asking the colorblind person to “be a bit more observant about colors”; they are simply not capable of it and it is folly to expect it of them, because no matter how hard they try, they can’t.
- But rather: “it upsets me when you joke about xyz; I know that probably doesn’t make sense to you and that’s ok, it doesn’t have to. I am asking, however, if you will please simply refrain from joking about xyz. Would you do that for me?”
Presented with such, it’s much more likely that the narcissist will drop their previous attempt to be good enough (by joking, because everyone loves someone with a sense of humor, right?) for a new, different attempt to be good enough (by showing “behold, look, I am a good person and doing the thing you asked, of which I am capable”).
That’s just one example, but the same methodology can be applied to most things.
For tricks pertaining to how to communicate such things without causing undue resistance, see:
Seriously Useful Communication Skills
Take care!
Don’t Forget…
Did you arrive here from our newsletter? Don’t forget to return to the email to continue learning!
Learn to Age Gracefully
Join the 98k+ American women taking control of their health & aging with our 100% free (and fun!) daily emails:
-
The Obesity Code – by Dr. Jason Fung
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.
Firstly, if you have already read Dr. Fung’s other book, The Diabetes Code, which we reviewed a little while ago, you can probably skip this one. It has mostly the same information, presented with a different focus.
While The Diabetes Code assumes you are diabetic, or prediabetic, or concerned about avoiding/reversing those conditions, The Obesity Code assumes you are obese, or heading in that direction, or otherwise are concerned about avoiding/reversing obesity.
What it’s not, though, is a weight loss book. Will it help if you want to lose weight? Yes, absolutely. But there is no talk here of weight loss goals, nor any motivational coaching, nor week-by-week plans, etc.
Instead, it’s more an informative textbook. With exactly the sort of philosophy we like here at 10almonds: putting information into people’s hands, so everyone can make the best decisions for themselves, rather than blindly following someone else’s program.
Dr. Fung explains why various dieting approaches don’t work, and how we can work around such things as our genetics, as well as most external factors except for poverty. He also talks us through how to change our body’s insulin response, and get our body working more like a lean machine and less like a larder for hard times.
Bottom line: this is a no-frills explanation of why your body does what it does when it comes to fat storage, and how to make it behave differently about that.
Don’t Forget…
Did you arrive here from our newsletter? Don’t forget to return to the email to continue learning!
Learn to Age Gracefully
Join the 98k+ American women taking control of their health & aging with our 100% free (and fun!) daily emails: