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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Cherries vs Cranberries – Which is Healthier?
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Our Verdict
When comparing cherries to cranberries, we picked the cherries.
Why?
In terms of macros, cherries have a little more protein (but it’s not much) while cranberries have a little more fiber. Despite this, cherries have the lower glycemic index—about half that of cranberries.
In the category of vitamins, cherries have a lot more of vitamins A, B1, B2, B3, B9, and a little more choline, while cranberries have more of vitamins B5, B6, C, E, and K. A modest win for cherries here.
When it comes to minerals, things are more divided: cherries have more calcium, copper, iron, magnesium, phosphorus, potassium, and zinc, while cranberries have more manganese. An easy win for cherries here.
This all adds up to a total win for cherries, but both of these fruits are great and both have their own beneficial properties (see our main features below!)
Want to learn more?
You might like to read:
- Cherries’ Very Healthy Wealth Of Benefits!
- Health Benefits Of Cranberries (But: You’d Better Watch Out)
Take care!
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A Cold Shower A Day Keeps The Doctor Away?
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A Cold Shower A Day Keeps The Doctor Away?
This is Dutch extreme athlete Wim Hof, also known as “The Iceman”! He’s broken many world records mostly relating to the enduring the cold, for example:
- climbing Mount Kilimanjaro in shorts
- running a half-marathon above the Arctic Circle barefoot
- standing in a container completely covered with ice cubes for more than 112 minutes
You might not want to do yoga in your pyjamas on an iceberg, but you might like…
- better circulatory health
- reduced risk of stroke
- a boosted immune system
- healthier skin
- more energy and alertness
…and things like that. Wim Hof’s method is not just about extreme athletic achievements; most of what he does, the stuff that can benefit the rest of us, is much more prosaic.
The Wim Hof Method
For Wim Hof, three things are key:
- Breathing (See: Wim Hof Method Breathing Exercises)
- Commitment (See: How to Increase Willpower)
- Cold therapy (See: Benefits of Cold Therapy)
Today, we’re going to be focusing on the last one there.
What are the benefits of Cold Therapy?
Once upon a time, we didn’t have central heating, electric blankets, thermal underwear, and hot showers. In fact, once upon a time, we didn’t have houses or clothes. We used to be a lot more used to the elements! And while it’s all well and good to enjoy modern comforts, it has left our bodies lacking practice.
Practice at what? Most notably: vasodilation and vasoconstriction, in response to temperature changes. Either:
- vasodilation, because part of our body needs more blood to keep it warm and nourished, or
- vasoconstriction, because part of our body needs less blood running through it to get cooled down.
Switching between the two gives the blood vessels practice at doing it, and improves vascular muscle tone. If your body doesn’t get that practice, your blood vessels will be sluggish at making the change. This can cause circulation problems, which in turn have a big impact in many other areas of health, including:
- cardiovascular disease
- stroke risk
- mood instability
- nerve damage in extremities
On the flipside, if the blood vessels do get regular practice at dilating and constricting, you might enjoy lower risk of those things, and instead:
- improved immune response
- healthier skin
- better quality sleep
- more energy and alertness
- improved sexual performance/responsiveness
So, how to get that, without getting extreme?
As today’s title suggests, “a cold shower a day” is a great practice.
You don’t have to jump straight in, especially if you think your circulation and vascular responses might be a bit sluggish in the first instance. In fact, Wim Hof recommends:
- Week 1: Thirty seconds of cold water at the end of a warm shower each morning
- Week 2: One minute of cold water at the end of a warm shower each morning
- Week 3: A minute and a half of cold water at the end of a warm shower each morning
- Week 4: Two minutes of cold water at the end of a warm shower each morning
How cold is cold?
The benefits of cold exposure begin at around 16ºC / 60ºF, so in most places, water from the cold water mains is sufficiently cold.
As your body becomes more used to making the quick-change on a vascular level, the cold water will seem less shocking to your system. In other words, on day 30 it won’t hit you like it did on day one.
At that point, you can either continue with your two-minutes daily cold shower, and reap the benefits, or if you’re curious to push it further, that’s where ice baths come in!
Can anyone do it, or are any conditions contraindicated?
As ever, we’re a health and productivity newsletter, not doctors, let alone your doctors. Nothing here is medical advice. However, Wim Hof himself says:
❝Listen to your body, and never force the practices. We advise against doing Wim Hof Method if you are dealing with any of the following:
- Epilepsy
- High blood pressure
- Coronary heart disease
- A history of serious healthy issues like heart failure or stroke
- Pregnancy*
- Childhood*❞
*There is simply not enough science regarding the effects of cold exposure on people who are pregnant, or children. Obviously, we don’t expect this to be remedied anytime soon, because the study insitutions’ ethics boards would (rightly!) hold up the study.
As for the other conditions, and just generally if unsure, consult a doctor.
As you can see, this does mean that a limitation of Cold Therapy is that it appears to be far better as a preventative, since it helps guard against the very conditions that could otherwise become contraindications.
We haven’t peppered today’s main feature with study papers, partly because Wim Hof’s own website has kindly collated a collection of them (with links and summaries!) onto one page:
Further reading: The Science Behind The Wim Hof Method
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Slowing the Progression of Cataracts
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Understanding Cataracts
Cataracts are natural and impact everyone.
That’s a bit of a daunting opening line, but as Dr. Michele Lee, a board-certified ophthalmologist, explains, cataracts naturally develop with age, and can be accelerated by factors such as trauma, certain medications, and specific eye conditions.
We know how important your vision is to you (we’ve had great feedback about the book Vision for Life) as well as our articles on how glasses impact your eyesight and the effects of using eye drops.
While complete prevention isn’t possible, steps such as those mentioned below can be taken to slow their progression.
Here is an overview of the video’s first 3 takeaways. You can watch the whole video below.
Protect Your Eyes from Sunlight
Simply put, UV light damages lens proteins, which (significantly) contributes to cataracts. Wearing sunglasses can supposedly prevent up to 20% of cataracts caused by UV exposure.
Moderate Alcohol Consumption
We all, at some level, know that alcohol consumption doesn’t do us any good. Your eye health isn’t an exception to the rule; alcohol has been shown to contribute to cataract development.
If you’re looking at reducing your alcohol use, try reading this guide on lowering, or eradicating, alcohol consumption.
Avoid Smoking
Smokers are 2-3 times more likely to develop cataracts. Additionally, ensure good ventilation while cooking to avoid exposure to harmful indoor smoke.
See all 5 steps in the below video:
How was the video? If you’ve discovered any great videos yourself that you’d like to share with fellow 10almonds readers, then please do email them to us!
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The FIRST Program: Fighting Insulin Resistance with Strength Training – by Dr. William Shang
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A lot of advice about fighting insulin resistance focuses on diet. And, that’s worthwhile! How we eat does make a huge difference to our insulin responses (as does fasting). But, we expect our regular 10almonds readers either know these things now, or can read one of several very good books we’ve already reviewed about such.
This one’s different: it focuses, as the title promises, on fighting insulin resistance with strength training. And why?
It’s because of the difference that our body composition makes to our metabolism. Now, our body fat percentage is often talked about (or, less usefully but more prevalently, even if woefully misleadingly, our BMI), but Dr. Shang makes the case for it being our musculature that has the biggest impact; because of how it hastens our metabolism, and because of how it is much healthier for the body to store glycogen in muscle tissue, than just cramming whatever it can into the liver and visceral fat. It becomes relevant, then, that there’s a limit to how much glycogen can be stored in muscle tissue, and that limit is how much muscle you have.
This is not, however, 243 pages to say “lift some weights, lazybones”. Rather, he explains the relevant pathophysiology (we will be more likely to adhere to things we understand, than things we do not), and gives practical advice on exercising the different kinds of muscle fibers, arguing that the whole is greater than the sum of its parts, as well as outlining an exercise program for the gym, plus a chapter on no-gym exercises too.
The style is quite dense, which may be offputting for some, but it suffices to take one’s time and read thoughtfully; the end result is worth it.
Bottom line: if you’d like to keep insulin resistance at bay, this book is an excellent extra tool for that.
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3 Day Juice Fasting? Not So Fast!
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Juice fasts are trending… Again. They have been before, and this will probably not be the last time either.
The rationale is that by having nothing but fruit and/or vegetable juice for a few days, the body can clear itself of toxins while it’s not being preoccupied by dealing with what you’re eating on a daily basis.
This is not bad in theory, and in fact is a sort of parallel to the actually good advice to help the liver regenerate—by abstaining from things that the liver has to do hard work about, it has more internal resources to devote to taking care of itself.
Learn more about this: How To Unfatty A Fatty Liver
Just one problem
By having only juice for a few days, you are doing the opposite of what the liver needs.
In fact, by giving it what’s basically straight sugars in water with no fiber and not even any fats to slow it down, you are making your liver work overtime to deal with the flood of sugars, and it will not cope well.
Indeed, processed carbs without sufficient fiber are one of the main drivers of non-alcoholic fatty liver disease.
And yes, that’s what juice is: processed carbs without fiber
(juicing is a process!)
You can read more about the science of that, here:
From Apples to Bees, and High-Fructose Cs: Which Sugars Are Healthier, And Which Are Just The Same? ← we get into quite some detail about how, exactly, such a harmless-seeming thing as fruit juice messes up the liver so badly
Here be (more) science
A three-day interventional study was performed on juicing and microbiome health, with three groups:
- Juice only
- Juice with whole foods
- Only whole plant-based foods
The results?
- Juice only: biggest growth in bacteria that cause inflammation and gut permeability (that’s bad; very bad)
- Juice with whole foods: the same bad effects, but much less pronounced than the juice-only group
- Only whole plant-based food: notable improvements in the microbiome
That’s what the changes were immediately post-intervention; what’s interesting to note is that the bad effects of the juice-only group also lingered longer, whereas the juice+food group enjoyed a relatively quicker recovery in the two weeks after the intervention.
Here’s the paper itself; be warned, you’ll be reading a lot about feces and saliva alongside eating and drinking:
Effects of Vegetable and Fruit Juicing on Gut and Oral Microbiome Composition
Ok, what can I do to detox?
Well, the advice we gave up top in the linked article about liver health is very sound, and also you might like to check out:
Detox: What’s Real, What’s Not, What’s Useful, What’s Dangerous?
Want to learn more?
Here’s a video explainer from the ever-charming French biochemist Jessie Inchauspé (and our own text overview, for those who prefer reading):
Fruit Is Healthy; Juice Isn’t (Here’s Why)
Take care!
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Elderly loss of energy
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It’s Q&A Day at 10almonds!
Have a question or a request? You can always hit “reply” to any of our emails, or use the feedback widget at the bottom!
In cases where we’ve already covered something, we might link to what we wrote before, but will always be happy to revisit any of our topics again in the future too—there’s always more to say!
As ever: if the question/request can be answered briefly, we’ll do it here in our Q&A Thursday edition. If not, we’ll make a main feature of it shortly afterwards!
So, no question/request too big or small
❝Please please give some information on elderly loss of energy and how it can be corrected. Please!❞
A lot of that is the metabolic slump described above! While we certainly wouldn’t describe 60 as elderly, and the health impacts from those changes at 45–55 get a gentler curve from 60 onwards… that curve is only going in one direction if we don’t take exceptionally good care of ourselves.
And of course, there’s also a degree of genetic lottery, and external factors we can’t entirely control (e.g. injuries etc).
One factor that gets overlooked a lot, though, is really easy to fix: B-vitamins.
In particular, vitamins B1, B5, B6, and B12. Of those, especially vitamins B1 and B12.
(Vitamins B5 and B6 are critical to health too, but relatively few people are deficient in those, while many are deficient in B1 and/or B12, especially as we get older)
Without going so detailed as to make this a main feature: these vitamins are essential for energy conversion from food, and they will make a big big difference.
You might especially want to consider taking sulbutiamine, which is a synthetic version of thiamin (vitamin B1), and instead of being water-soluble, it’s fat-soluble, and it easily crosses the blood-brain barrier, which is a big deal.
As ever, always check with your doctor because your needs/risks may be different. Also, there can be a lot of reasons for fatigue and you wouldn’t want to overlook something important.
You might also want to check out yesterday’s sponsor, as they offer personalized at-home health testing to check exactly this sort of thing.
❝What are natural ways to lose weight after 60? Taking into account bad knees or ankles, walking may be out as an exercise, running certainly is.❞
Losing weight is generally something that comes more from the kitchen than the gym, as most forms of exercise (except HIIT; see below) cause the metabolism to slow afterwards to compensate.
However, exercise is still very important, and swimming is a fine option if that’s available to you.
A word to the wise: people will often say “gentle activities, like tai chi or yoga”, and… These things are not the same.
Tai chi and yoga both focus on stability and suppleness, which are great, but:
- Yoga is based around mostly static self-support, often on the floor
- Tai chi will have you very often putting most of your weight on one slowly-increasingly bent knee at a time, and if you have bad knees, we’ll bet you winced while reading that.
So, maybe skip tai chi, or at least keep it to standing meditations and the like, not dynamic routines. Qigong, the same breathing exercises used in tai chi, is also an excellent way to improve your metabolism, by the way.
Ok, back onto HIIT:
You might like our previous article: How To Do HIIT* (Without Wrecking Your Body)
*High-Intensity Interval Training (the article also explains what this is and why you want to do it)
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