Meet Mark

Let me introduce myself. My name is Mark Sisson. I’m 63 years young. I live and work in Malibu, California. In a past life I was a professional marathoner and triathlete. Now my life goal is to help 100 million people get healthy. I started this blog in 2006 to empower people to take full responsibility for their own health and enjoyment of life by investigating, discussing, and critically rethinking everything we’ve assumed to be true about health and wellness...

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Tag: hormones

Sound Cues and Circadian Rhythms

Yesterday, I showed how environmental, behavioral, and social cues act as zeitgebers to human circadian rhythms, and I tried to be as thorough as possible (without outstaying my welcome). I left out one very important environmental cue with the promise of more information today – sound.

I can’t recall exactly where I heard about it, but it was someone’s offhand reference to the notion of the calls of songbirds affecting our circadian rhythms that convinced me I should do a follow-up to the blue light piece from earlier this year. The notion of bird calls affecting us on a deeper level than a regular sound makes some intuitive sense to me, so I did some searching to see if there was anything to it.

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A Different Perspective on Hypothyroidism

Hypothyroid has been covered to death before. I’m particularly fond of The Healthy Skeptic’s coverage – check out Chris Kresser’s ongoing series (possibly before you read on) for some great information on the thyroid. Carnivorous Danny Roddy did a good piece on it last year as well. As such, I won’t be redoing or rehashing an “intro to thyroid.” Instead, I’ll give a brief overview and then discuss why I think some of us may be looking at thyroid “dysfunction” in the wrong light.

The thyroid is a complicated little bugger wielding a lot of influence over the metabolism, and it seems like just about anything has been fingered as a trigger of its dysfunction. Lack of carbs in the diet, too few calories, too much iodine, too little iodine, too many grains, intermittent fasting, excessive cortisol, and multiple other factors have gotten the blame. Unraveling the multiple potential triggers for its dysfunction can be tough. But is dysfunction always the right way to describe a slight reduction in thyroid hormones? I’m not so sure.

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A Primal Primer: Estrogen

The human endocrine system exists in a state of delicate balance. None of its constituents function in a vacuum, and trying to explain every hormonal interrelationship would take volumes, but one statement is fairly safe to make: one hormone affects another. Secreting one often inhibits the next, which in turn sets off an entirely different chain reaction of hormonal secretions, inhibitions, and syntheses. I almost feel like trying to micromanage your entire endocrine system is tedious and counterproductive (and probably impossible to do effectively). I much prefer to simply eat right, exercise smart, get good sleep, normalize stress, and take advantage of simple lifestyle hacks. Still, it doesn’t hurt to understand some of the major hormonal players, especially one as widely maligned by the strength and fitness community as estrogen.

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Testosterone: Not So Manly After All?

Last week’s primer on testosterone garnered a ton of responses, mostly positive, but there appeared to be a bit of confusion regarding testosterone’s role in the female body. Namely, folks seemed to think I was suggesting it played almost no role at all! I tried to be as clear as possible – testosterone is an absolutely vital hormone for women – but I’ll try to be clearer. There’s just that niggling, pervasive stigma of testosterone as the sole hormonal realm of big burly men with bulging muscles, and I guess it’s hard to shake, even for my enlightened readership. Perhaps it’s because we’ve been subject to years of simplistic, substandard health and nutrition advice, black-and-white proclamations that attempt to describe the complex inner workings of the human body with a few sentences.

Fat is bad! Whole grains good! Men make testosterone! Women make estrogen!

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A Primal Primer: Testosterone

If you’ve been reading recently you know I’ve been on a hormone kick recently. That sexy looking molecule to the right and the hormone du jour: testosterone. Testosterone is the principal anabolic and sex hormone in humans, responsible for sexual desire and function, muscular hypertrophy, densification of bones, and hair growth. Compared to females, males famously produce about ten times the amount of testosterone, but females are far more sensitive to its effects. Though testosterone is largely responsible for those traits and characteristics that are considered “masculine” – physical strength, body hair, dominance, and virility – both sexes require it for proper sexual and physical development. In mammals, males secrete it primarily from the testicles (about 95% of the total amount, in fact) and women secrete it from the ovaries. A modicum is produced in the adrenal glands in both sexes.

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Further Adventures with Leptin

I mentioned a few of the working hypotheses for avoiding leptin resistance in my posts last week, including fructose and lectin avoidance, getting adequate nightly sleep, and eating at or above maintenance levels – or at least throwing in periodic carb refeeds – but there’s even more involved in establishing a good relationship with your leptin levels and leptin sensitivity. Depending on your general approach to life, this could be good news or bad news. It’s either more stuff to worry about, or more ways to buttress your health. As I alluded to last week, experimenting with carb refeeding and leptin manipulation within the broader Primal Blueprint eating style is butter on the steak (because “icing on the cake” just won’t do for us Primal folks).

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Primal Advice for Acne Sufferers

Included among last week’s “Ask Me Anything” responses were several requests for a Primal commentary on acne. A lot of people have asked for this kind of post over the years. The fact is, it’s a great question. Acne is a common problem that gives too many people too much grief. Our medical establishment’s prescription for acne generally involves dehydrating the skin into oblivion, sandblasting it with chemicals, or pumping hormones, antibiotics and potentially toxic meds into the patient. (If any of these methods have worked for you, I mean no offense. I just think people deserve better options than these.) Is there a healthier, more Primal method to a clear complexion? In a nutshell, yes. I’m not talking rabbit-in-a-hat trick but a lifestyle approach with natural options that minimize the systemic and external conditions associated with acne. Let’s look at the full picture.

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Primal Nutrition and Fertility

Although for many of us starting a family simply happens (surprise!), others among us take an intentional approach. Maybe we delay having children for professional, financial or relationship reasons. Maybe we begin trying when we’re young. Regardless of timing, facing our fertility (so to speak) is an intensely personal and often emotional passage. It can inspire joy and wonder in our basic human capacities – our deep-seated physical impulse and emotional expansion toward parenthood. For some of us, however, the journey takes on anxiety and disappointment. Although varied and nuanced factors define our reproductive health (some not fully understood even today in the medical community), experts agree that lifestyle factors contribute to overall fertility.

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Dear Mark: Post-Workout Fasting

Before I jump into this week’s Dear Mark post I wanted to direct everyone’s attention to Andrew Rubalcava’s site, Go Healthy Go Fit. Andrew just published an interview with me. Here are just a few of the questions I answered:
Who have been your top 3 favorite bloggers over the years?
How did you get involved in physical competition such as your experience as a triathlete?
If you could give a few words of advice for those who are just beginning to enter a world of health and fitness, what would you say?
Check out the interview here, and check back on Thursday when I’ll be publishing Andrew’s guest post on how to stay healthy no matter what type of lifestyle you lead.

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Hormones and Heart Disease

We aren’t talking estrogen here, but this latest news does concern the ladies of the community.

In the recent “Hunt Study” conducted by researchers at the Norwegian University of Science, women with thyroid function in the less active part of the “normal” clinical reference range showed an increased risk for fatal coronary heart disease relative to those with numbers in the more active part of the clinical range.

The findings were based on a follow-up with 17,311 women and 8,002 men who had shown no signs of heart disease, diabetes or thyroid disorder at the beginning of the study in the mid-1990s. All participants were 40 years or older when initial tests were done to measure levels of thyrotropin, a hormone released by the pituitary gland that is known to stimulate the thyroid. During the follow-up examinations that were completed in 2004, researchers found that 192 women and 164 men had died of heart disease. Of these subjects, none had shown signs of thyroid malfunction. However, women whose readings showed the relative lowest (but still clinically normal) thyroid gland activity were “69 percent more likely to die from heart disease than women with more active glands.”

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