Sleep Tracking, For Five Million Nights
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5 Sleep Phenotypes, By Actual Science
You probably know people can be broadly divided into “early birds” and “night owls”:
Early Bird Or Night Owl? Genes vs Environment
…and then the term “hummingbird” gets used for a person who flits between the two.
That’s three animals so far. If you read a book we reviewed recently, specifically this one:
The Power of When – by Dr. Michael Breus
…then you may have used the guide within to self-diagnose your circadian rhythm type (chronotype) according to Dr. Breus’s system, which divides people into bears, lions, wolves, and dolphins.
That’s another four animals. If you have a FitBit, it can “diagnose” you with being those and/or a menagerie of others, such as giraffe, hedgehog, parrot, and tortoise:
How Fitbit Developed the Sleep Profile Experience (Part 2 – Sleep Animals)
Five million nights
A team of researchers recently took a step away from this veritable zoo of 11 different animals and counting, and used a sophisticated modelling system to create a spatial-temporal map of people’s sleep habits, and this map created five main “islands” that people’s sleep habits could settle on, or sometimes move from island to island.
Those “five million nights” by the way? It was actually 5,095,798 nights! You might notice that would take from the 2020s to the 15970s to complete, so this was rather a matter of monitoring 33,152 individuals between January and October of the same year. Between them, they got those 5,095,798 nights of sleep (or in some cases, nights of little or no sleep, but still, they were there for the nights).
The five main phenotypes that the researchers found were:
- What we think of as “normal” sleep. In this phenotype, people get about eight hours of uninterrupted sleep for at least six days in a row.
- As above for half the nights, but they only sleep for short periods of time in bouts of less than three hours the other half.
- As per normal sleep, but with one interrupted night per week, consisting of a 5 hour sleep period and then broken sleep for a few more hours.
- As per normal sleep generally, but with occasional nights in which long bouts of sleep are separated by a mid-sleep waking.
- Sleeping for very short periods of time every night. This phenotype was the rarest the researchers found, and represents extremely disrupted sleep.
As you might suspect, phenotype 1 is healthier than phenotype 5. But that’s not hugely informational, as the correlation between getting good sleep and having good health is well-established. So, what did the study teach us?
❝We found that little changes in sleep quality helped us identify health risks. Those little changes wouldn’t show up on an average night, or on a questionnaire, so it really shows how wearables help us detect risks that would otherwise be missed.❞
More specifically,
❝We found that the little differences in how sleep disruptions occur can tell us a lot. Even if these instances are rare, their frequency is also telling. So it’s not just whether you sleep well or not – it’s the patterns of sleep over time where the key info hides❞
…and, which gets to the absolute point,
❝If you imagine there’s a landscape of sleep types, then it’s less about where you tend to live on that landscape, and more about how often you leave that area❞
In other words: if your sleep pattern is not ideal, that’s one thing and it’d probably be good to address it, by improving your sleep. However, if your sleep pattern changes phenotype without an obvious known reason why, this may be considered an alarm bell warning of something else that needs addressing, which may be an underlying illness or condition—meaning it can be worthwhile being a little extra vigilant when it comes to regular health screenings, in case something new has appeared.
Want to read more?
You can read the paper in full here:
Five million nights: temporal dynamics in human sleep phenotypes
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No, taking drugs like Ozempic isn’t ‘cheating’ at weight loss or the ‘easy way out’
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Hundreds of thousands of people worldwide are taking drugs like Ozempic to lose weight. But what do we actually know about them? This month, The Conversation’s experts explore their rise, impact and potential consequences.
Obesity medication that is effective has been a long time coming. Enter semaglutide (sold as Ozempic and Wegovy), which is helping people improve weight-related health, including lowering the risk of a having a heart attack or stroke, while also silencing “food noise”.
As demand for semaglutide increases, so are claims that taking it is “cheating” at weight loss or the “easy way out”.
We don’t tell people who need statin medication to treat high cholesterol or drugs to manage high blood pressure they’re cheating or taking the easy way out.
Nor should we shame people taking semaglutide. It’s a drug used to treat diabetes and obesity which needs to be taken long term and comes with risks and side effects, as well as benefits. When prescribed for obesity, it’s given alongside advice about diet and exercise.
How does it work?
Semaglutide is a glucagon-like peptide-1 receptor agonist (GLP-1RA). This means it makes your body’s own glucagon-like peptide-1 hormone, called GLP-1 for short, work better.
GLP-1 gets secreted by cells in your gut when it detects increased nutrient levels after eating. This stimulates insulin production, which lowers blood sugars.
GLP-1 also slows gastric emptying, which makes you feel full, and reduces hunger and feelings of reward after eating.
GLP-1 receptor agonist (GLP-1RA) medications like Ozempic help the body’s own GLP-1 work better by mimicking and extending its action.
Some studies have found less GLP-1 gets released after meals in adults with obesity or type 2 diabetes mellitus compared to adults with normal glucose tolerance. So having less GLP-1 circulating in your blood means you don’t feel as full after eating and get hungry again sooner compared to people who produce more.
GLP-1 has a very short half-life of about two minutes. So GLP-1RA medications were designed to have a very long half-life of about seven days. That’s why semaglutide is given as a weekly injection.
What can users expect? What does the research say?
Higher doses of semaglutide are prescribed to treat obesity compared to type 2 diabetes management (up to 2.4mg versus 2.0mg weekly).
A large group of randomised controlled trials, called STEP trials, all tested weekly 2.4mg semaglutide injections versus different interventions or placebo drugs.
Trials lasting 1.3–2 years consistently found weekly 2.4 mg semaglutide injections led to 6–12% greater weight loss compared to placebo or alternative interventions. The average weight change depended on how long medication treatment lasted and length of follow-up.
Higher doses of semaglutide are prescribed for obesity than for type 2 diabetes. fcm82/Shutterstock Weight reduction due to semaglutide also leads to a reduction in systolic and diastolic blood pressure of about 4.8 mmHg and 2.5 mmHg respectively, a reduction in triglyceride levels (a type of blood fat) and improved physical function.
Another recent trial in adults with pre-existing heart disease and obesity, but without type 2 diabetes, found adults receiving weekly 2.4mg semaglutide injections had a 20% lower risk of specific cardiovascular events, including having a non-fatal heart attack, a stroke or dying from cardiovascular disease, after three years follow-up.
Who is eligible for semaglutide?
Australia’s regulator, the Therapeutic Goods Administration (TGA), has approved semaglutide, sold as Ozempic, for treating type 2 diabetes.
However, due to shortages, the TGA had advised doctors not to start new Ozempic prescriptions for “off-label use” such as obesity treatment and the Pharmaceutical Benefits Scheme doesn’t currently subsidise off-label use.
The TGA has approved Wegovy to treat obesity but it’s not currently available in Australia.
When it’s available, doctors will be able to prescribe semaglutide to treat obesity in conjunction with lifestyle interventions (including diet, physical activity and psychological support) in adults with obesity (a BMI of 30 or above) or those with a BMI of 27 or above who also have weight-related medical complications.
What else do you need to do during Ozempic treatment?
Checking details of the STEP trial intervention components, it’s clear participants invested a lot of time and effort. In addition to taking medication, people had brief lifestyle counselling sessions with dietitians or other health professionals every four weeks as a minimum in most trials.
Support sessions were designed to help people stick with consuming 2,000 kilojoules (500 calories) less daily compared to their energy needs, and performing 150 minutes of moderate-to-vigorous physical activity, like brisk walking, dancing and gardening each week.
STEP trials varied in other components, with follow-up time periods varying from 68 to 104 weeks. The aim of these trials was to show the effect of adding the medication on top of other lifestyle counselling.
Trial participants also exercised for 150 minutes a week. Elena Nichizhenova/Shutterstock A review of obesity medication trials found people reported they needed less cognitive behaviour training to help them stick with the reduced energy intake. This is one aspect where drug treatment may make adherence a little easier. Not feeling as hungry and having environmental food cues “switched off” may mean less support is required for goal-setting, self-monitoring food intake and avoiding things that trigger eating.
But what are the side effects?
Semaglutide’s side-effects include nausea, diarrhoea, vomiting, constipation, indigestion and abdominal pain.
In one study these led to discontinuation of medication in 6% of people, but interestingly also in 3% of people taking placebos.
More severe side-effects included gallbladder disease, acute pancreatitis, hypoglycaemia, acute kidney disease and injection site reactions.
To reduce risk or severity of side-effects, medication doses are increased very slowly over months. Once the full dose and response are achieved, research indicates you need to take it long term.
Given this long-term commitment, and associated high out-of-pocket cost of medication, when it comes to taking semaglutide to treat obesity, there is no way it can be considered “cheating”.
Read the other articles in The Conversation’s Ozempic series here.
Clare Collins, Laureate Professor in Nutrition and Dietetics, University of Newcastle
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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Microplastics found in artery plaque linked with higher risk of heart attack, stroke and death
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Microplastics and nanoplastics are everywhere in our environment – including in our oceans and lakes, farmland, and even Arctic ice algae.
Microplastics have also been found inside of us – with studies detecting them in various tissues including in the lungs, blood, heart and placenta. Understandably, concern is rising about the potential risks of microplastics on our health.
However, while a growing body of research has focused on microplastics and nanoplastics, there’s still a lack of direct evidence that their presence in human tissues is harmful to our health – and it’s uncertain if they are related to particular diseases.
A new study has uncovered a correlation between microplastics and heart health, though. The researchers found that people who had detectable microplastics and nanoplastics in the plaque in their arteries had a higher risk of heart attack, stroke and death.
Heart health
The researchers looked at 257 people altogether. All of the patients were already undergoing preventative surgery to remove plaque from their carotid arteries (the main arteries that supply the brain with blood). This allowed the researchers to collect plaque samples and perform a chemical analysis. They then followed up with participants 34 months later.
Of the 257 participants, 150 were found to have the presence of microplastics and nanoplastics in their arterial plaque – mainly fragments of two of the most commonly used plastics in the world, polyethylene (used in grocery bags, bottles and food packaging) and polyvinyl chloride (used in flooring, cladding and pipes).
A statistical analysis of this data found that patients with microplastics and nanoplastics in their plaque had a higher risk of suffering a heart attack, stroke or death from any cause, compared with those who had no microplastics or nanoplastics in their plaque.
The researchers also analysed the macrophages (a type of immune cell that helps remove pathogens from the body) in the patients’ arteries. They found that participants who’d had microplastics and nanoplastics in their plaque also had evidence of plastic fragments in their macrophages.
They also looked at whether certain genes associated with inflammation (which can be a sign of disease) were switched on in the participants. They found that the participants who’d had microplastics and nanoplastics in their plaque also had signs of inflammation in their genes.
The microplastics were found in samples of plaque extracted from the carotid artery. Rocos/ Shutterstock These results may suggest an accumulation of nanoplastics and microplastics in carotid plaque could partly trigger inflammation. This inflammation may subsequently change the way plaque behaves in the body, making it less stable and triggering it to form a blood clot – which can eventually block blood flow, leading to heart attacks and strokes.
Interestingly, the researchers also found the presence of nanoplastics and microplastics was more common in participants who had diabetes and cardiovascular disease. This raises a lot of questions which have yet to be answered – such as why microplastics were more common in these participants, and if there may be a correlation between other diseases and the presence of microplastics in the body.
Other health risks
This study only focused on patients who had carotid artery disease and were already having surgery to remove the build-up of plaque. As such, it’s unclear whether the findings of this study can be applied to a larger population of people.
However, it isn’t the first study to show a link between microplastics and nanoplastics with poor health. Research suggests some of this harm may be due to the way microplastics and nanoplastics interact with proteins in the body.
For example, some human proteins adhere to the surface of polystyrene nanoplastics, forming a layer surrounding the nanoparticle. The formation of this layer may influence the activity and transfer of nanoplastics in human organs.
Another study suggested that nanoplastics can interact with a protein called alpha-synuclein, which in mouse studies has been shown to play a crucial role in facilitating communication between nerve cells. These clumps of nanoplastics and protein may increase the risk of Parkinson’s disease.
My published PhD research in chicken embryos found that nanoplastics may cause congenital malformations due to the way they interact with a protein called cadherin6B. Based on the interactions myself and fellow researchers saw, these malformations may affect the embryo’s eyes and neural tube, as well as the heart’s development and function.
Given the fact that nanoplastics and microplastics are found in carotid plaque, we now need to investigate how these plastics got into such tissues.
In mice, it has been demonstrated that gut macrophages (a type of white blood cell) can absorb microplastics and nanoplastics into their cell membrane. Perhaps a similar mechanism is taking place in the arteries, since nanoplastics have been identified in samples of carotid plaque macrophages.
The findings from this latest study add to a growing body of evidence showing a link between plastic products and our health. It is important now for researchers to investigate the specific mechanisms by which microplastics and nanoplastics cause harm in the body.
Meiru Wang, Postdoctoral Researcher, Molecular Biology and Nanotoxicology, Leiden University
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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The Distracted Mind – by Dr. Adam Gazzaley and Dr. Larry Rosen
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Yes, yes, we know, unplug once in a while. But what else do this highly-qualified pair of neuroscientists have to offer?
Rather than being a book for the sake of being a book, with lots of fluff and the usual advice about single-tasking, the authors start with a reframe:
Neurologically speaking, the hit of dopamine we get when looking for information is the exact same as the hit of dopamine that we, a couple of hundred thousand years ago, got when looking for nuts and berries.
- When we don’t find them, we become stressed, and search more.
- When we do find them, we are encouraged and search more nearby, and to the other side of nearby, and near around, to find more.
But in the case of information (be it useful information or celebrity gossip or anything in between), the Internet means that’s always available now.
So, we jitter around like squirrels, hopping from one to the next to the next.
A strength of this book is where it goes from there. Specifically, what evidence-based practices will actually keep our squirrel-brain focused… and which are wishful thinking for anyone who lives in this century.
Bringing original research from their own labs, as well as studies taken from elsewhere, the authors present a science-based toolkit of genuinely useful resources for actual focus.
Bottom line: if you think you could really optimize your life if you could just get on track and stay on track, this is the book for you.
Click here to check out The Distracted Mind, and get yours to focus!
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Recognize The Early Symptoms Of Parkinson’s Disease
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Parkinson’s disease is a degenerative condition with wide-reaching implications for health. While there is currently no known cure, there are treatments, so knowing about it sooner rather than later is important.
Spot The Signs
There are two main kinds of symptoms, motor and non-motor.
Motor symptoms include:
- trembling that occurs when muscles are relaxed; often especially visible in the fingers
- handwriting changes—not just because of the above, but also often getting smaller
- blank expression, on account of fewer instruction signals getting through to the face
- frozen gait—especially difficulty starting walking, and a reduced arm swing
Non-motor symptoms include:
- loss of sense of smell—complete, or a persistent reduction of
- sleepwalking, or sleep-talking, or generally acting out dreams while asleep
- constipation—on an ongoing basis
- depression/anxiety, especially if there was no prior history of these conditions
For more detail on each of these, as well as what steps you might want to take, check out what Dr. Luis Zayas has to say:
Click Here If The Embedded Video Doesn’t Load Automatically!
Want to learn more?
You might also like to read:
Citicoline vs Parkinson’s (And More)
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Managing Jealousy
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Jealousy is often thought of as a young people’s affliction, but it can affect us at any age—whether we are the one being jealous, or perhaps a partner.
And, the “green-eyed monster” can really ruin a lot of things; relationships, friendships, general happiness, physical health even (per stress and anxiety and bad sleep), and more.
The thing is, jealousy looks like one thing, but is actually mostly another.
Jealousy is a Scooby-Doo villain
That is to say: we can unmask it and see what much less threatening thing is underneath. Which is usually nothing more nor less than: insecurities
- Insecurity about losing one’s partner
- Insecurity about not being good enough
- Insecurity about looking bad socially
…etc. The latter, by the way, is usually the case when one’s partner is socially considered to be giving cause for jealousy, but the primary concern is not actually relational loss or any kind of infidelity, but rather, looking like one cannot keep one’s partner’s full attention romantically/sexually. This drives a lot of people to act on jealousy for the sake of appearances, in situations where they might otherwise, if they didn’t feel like they’d be adversely judged for it, be considerably more chill.
Thus, while monogamy certainly has its fine merits, there can also be a kind of “toxic monogamy” at hand, where a relationship becomes unhealthy because one partner is just trying to live up to social expectations of keeping the other partner in check.
This, by the way, is something that people in polyamorous and/or open relationships typically handle quite neatly, even if a lot of the following still applies. But today, we’re making the statistically safe assumption of a monogamous relationship, and talking about that!
How to deal with the social aspect
If you sit down with your partner and work out in advance the acceptable parameters of your relationship, you’ll be ahead of most people already. For example…
- What counts as cheating? Is it all and any sex acts with all and any people? If not, where’s the line?
- What about kissing? What about touching other body parts? If there are boundaries that are important to you, talk about them. Nothing is “too obvious” because it’s astonishing how many times it will happen that later someone says (in good faith or not), “but I thought…”
- What about being seen in various states of undress? Or seeing other people in various states of undress?
- Is meaningless flirting between friends ok, and if so, how do we draw the line with regard to what is meaningless? And how are we defining flirting, for that matter? Talk about it and ensure you are both on the same page.
- If a third party is possibly making moves on one of us under the guise of “just being friendly”, where and how do we draw the line between friendliness and romantic/sexual advances? What’s the difference between a lunch date with a friend and a romantic meal out for two, and how can we define the difference in a way that doesn’t rely on subjective “well I didn’t think it was romantic”?
If all this seems like a lot of work, please bear in mind, it’s a lot more fun to cover this cheerfully as a fun couple exercise in advance, than it is to argue about it after the fact!
See also: Boundary-Setting Beyond “No”
How to deal with the more intrinsic insecurities
For example, when jealousy is a sign of a partner fearing not being good enough, not measuring up, or perhaps even losing their partner.
The key here might not shock you: communication
Specifically, reassurance. But critically, the correct reassurance!
A partner who is jealous will often seek the wrong reassurance, for example wanting to read their partner’s messages on their phone, or things like that. And while a natural desire when experiencing jealousy, it’s not actually helpful. Because while incriminating messages could confirm infidelity, it’s impossible to prove a negative, and if nothing incriminating is found, the jealous partner can just go on fearing the worst regardless. After all, their partner could have a burner phone somewhere, or a hidden app for cheating, or something else like that. So, no reassurance can ever be given/gained by such requests (which can also become unpleasantly controlling, which hopefully nobody wants).
A quick note on “if you have nothing to fear, you have nothing to hide”: rhetorically that works, but practically it doesn’t.
Writer’s example: when my late partner and I formalized our relationship, we discussed boundaries, and I expressed “so far as I am concerned, I have no secrets from you, except secrets that are not mine to share. For example, if someone has confided in me and asked that I not share it, I won’t. Aside from that, you have access-all-areas in my life; me being yours has its privileges” and this policy itself would already pre-empt any desire to read my messages.
Now indeed, I had nothing to hide. I am by character devoted to a fault. But my friends may well sometimes have things they don’t want me to share, which made that a necessary boundary to highlight (which my partner, an absolute angel by the way and not prone to unhealthy manifestations of jealousy in any case, understood completely).
So, it is best if the partner of a jealous person can explain the above principles as necessary, and offer the correct reassurance instead. Which could be any number of things, but for example:
- I am yours, and nobody else has a chance
- I fully intend to stay with you for life
- You are the best partner I have ever had
- Being with you makes my life so much better
…etc. Note that none of these are “you don’t have to worry about so-and-so”, or “I am not cheating on you”, etc, because it’s about yours and your partner’s relationship. If they ask for reassurances with regard to other people or activities, by all means state them as appropriate, but try to keep the focus on you two.
And if your partner (or you, if it’s you who’s jealous) can express the insecurity in the format…
“I’m afraid of _____ because _____”
…then the “because” will allow for much more specific reassurance. We all have insecurities, we all have reasons we might fear not being good enough for our partner, or losing their affection, and the best thing we can do is choose to trust our partners at least enough to discuss those fears openly with each other.
See also: Save Time With Better Communication ← this can avoid a lot of time-consuming arguments
What about if the insecurity is based in something demonstrably correct?
By this we mean, something like a prior history of cheating, or other reasons for trust issues. In such a case, the jealous partner may well have a reason for their jealousy that isn’t based on a personal insecurity.
In our previous article about boundaries, we talked about relationships (romantic or otherwise) having a “price of entry”. In this case, you each have a “price of entry”:
- The “price of entry” to being with the person who has previously cheated (or similar), is being able to accept that.
- And for the person who cheated (or similar), very likely their partner will have the “price of entry” of “don’t do that again, and also meanwhile accept in good grace that I might be jittery about it”.
And, if the betrayal of trust was something that happened between the current partners in the current relationship, most likely that was also traumatic for the person whose trust was betrayed. Many people in that situation find that trust can indeed be rebuilt, but slowly, and the pain itself may also need treatment (such as therapy and/or couples therapy specifically).
See also: Relationships: When To Stick It Out & When To Call It Quits ← this covers both sides
And finally, to finish on a happy note:
Only One Kind Of Relationship Promotes Longevity This Much!
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From straight to curly, thick to thin: here’s how hormones and chemotherapy can change your hair
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Head hair comes in many colours, shapes and sizes, and hairstyles are often an expression of personal style or cultural identity.
Many different genes determine our hair texture, thickness and colour. But some people’s hair changes around the time of puberty, pregnancy or after chemotherapy.
So, what can cause hair to become curlier, thicker, thinner or grey?
Curly or straight? How hair follicle shape plays a role
Hair is made of keratin, a strong and insoluble protein. Each hair strand grows from its own hair follicle that extends deep into the skin.
Curly hair forms due to asymmetry of both the hair follicle and the keratin in the hair.
Follicles that produce curly hair are asymmetrical and curved and lie at an angle to the surface of the skin. This kinks the hair as it first grows.
The asymmetry of the hair follicle also causes the keratin to bunch up on one side of the hair strand. This pulls parts of the hair strand closer together into a curl, which maintains the curl as the hair continues to grow.
Follicles that are symmetrical, round and perpendicular to the skin surface produce straight hair.
Each hair strand grows from its own hair follicle.
Mosterpiece/ShutterstockLife changes, hair changes
Our hair undergoes repeated cycles throughout life, with different stages of growth and loss.
Each hair follicle contains stem cells, which multiply and grow into a hair strand.
Head hairs spend most of their time in the growth phase, which can last for several years. This is why head hair can grow so long.
Let’s look at the life of a single hair strand. After the growth phase is a transitional phase of about two weeks, where the hair strand stops growing. This is followed by a resting phase where the hair remains in the follicle for a few months before it naturally falls out.
The hair follicle remains in the skin and the stems cells grow a new hair to repeat the cycle.
Each hair on the scalp is replaced every three to five years.
Each hair on the scalp is replaced every three to five years.
Just Life/ShutterstockHormone changes during and after pregnancy alter the usual hair cycle
Many women notice their hair is thicker during pregnancy.
During pregnancy, high levels of oestrogen, progesterone and prolactin prolong the resting phase of the hair cycle. This means the hair stays in the hair follicle for longer, with less hair loss.
A drop in hormones a few months after delivery causes increased hair loss. This is due to all the hairs that remained in the resting phase during pregnancy falling out in a fairly synchronised way.
Hair can change around puberty, pregnancy or after chemotherapy
This is related to the genetics of hair shape, which is an example of incomplete dominance.
Incomplete dominance is when there is a middle version of a trait. For hair, we have curly hair and straight hair genes. But when someone has one curly hair gene and one straight hair gene, they can have wavy hair.
Hormonal changes that occur around puberty and pregnancy can affect the function of genes. This can cause the curly hair gene of someone with wavy hair to become more active. This can change their hair from wavy to curly.
Researchers have identified that activating specific genes can change hair in pigs from straight to curly.
Chemotherapy has very visible effects on hair. Chemotherapy kills rapidly dividing cells, including hair follicles, which causes hair loss. Chemotherapy can also have genetic effects that influence hair follicle shape. This can cause hair to regrow with a different shape for the first few cycles of hair regrowth.
Your hair can change at different stages of your life.
Igor Ivakhno/ShutterstockHormonal changes as we age also affect our hair
Throughout life, thyroid hormones are essential for production of keratin. Low levels of thyroid hormones can cause dry and brittle hair.
Oestrogen and androgens also regulate hair growth and loss, particularly as we age.
Balding in males is due to higher levels of androgens. In particular, high dihydrotestosterone (sometimes shortened to DHT), which is produced in the body from testosterone, has a role in male pattern baldness.
Some women experience female pattern hair loss. This is caused by a combination of genetic factors plus lower levels of oestrogen and higher androgens after menopause. The hair follicles become smaller and smaller until they no longer produce hairs.
Reduced function of the cells that produce melanin (the pigment that gives our hair colour) is what causes greying.
Theresa Larkin, Associate professor of Medical Sciences, University of Wollongong
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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