Estrogen Throughout the Lifespan, Brain vs. Biological Aging, and The LE8
July Midlife Roundup [2025]
I finally finished some things I’d been putting off for years during my break. First, I took my desktop computer in which is slow, only to find it was on its last leg. I also did aptitude testing and will talk about that in a future post.
I’m also committed to making The Big Leap (see book review here) and I’m doing the Your Big Leap Year workbook. Every morning, I read a page and meditate on it while doing 20 minutes of slow breathing.
Wanna to join me?
I recently read that presenting things in threes aids people’s memory. So, I’m going to experiment with that in my posts and this round up.
The three keys in this post start with social media fact check about estrogen. Next, we’ll look at a new brain MRI study on middle-aged women and men–and what it means. And last, what’s missing in the headlines about midlife women and sleep?
Let’s go.
Estrogen throughout the lifespan
I stumbled on this chart, and I’ve seen similar ones tons of times on social media. It can be very scary to think you only have a “foot’s worth” of estrogen when you get older.
This is not representative of the truth and there is no citation, which I think is always necessary to support claims.
First off, estrogen levels aren’t linear, as shown. In fact, research shows there’s an increase of estrogen in infant girls. There're individual differences as well. Also, once women have a cycle, their estrogen levels fluctuate, making the entire premise questionable.
Also, once the ovaries stop making estrogen, a woman may get a brief surge or two after menopause, but levels should be relatively steady from that point on.
In fact, a 2019 study with women in their 70s suggests they have higher levels of estrone and testosterone.
Last, showing estrogen levels up to the neck feels like a scare tactic. This chart is a lot more accurate way to show blood levels of estrogen including the different types.
And let’s not forget, cells can make estrogen with the enzyme aromatase, and this doesn’t appear in blood tests, which charts and graphs like the above cannot explain.
All in all, a big thumbs down on this one!
Pace of Aging
I kept seeing headlines about MRIs predicting how fast people age. I finally looked at the study published in the July 1st edition of Nature Aging, realizing it was the Dunedin study.
I love that study!
The reason? The researchers use a life stage approach, drawing on data from 1037 New Zealanders studied since birth (1972-1973) to age 45.
Every few years (26, 32, 38 and 45), these researchers measure about 19 biomarkers (breathing is included in bold!) listed below and also tests on physical and cognitive function.
BMI, waist/hip ratio, HbA1c, leptin, blood pressure (mean arterial pressure), cardiorespiratory fitness (VO2max), forced vital capacity ratio (FEV1/FVC), FEV1, total cholesterol, triglycerides, HDL, lipoprotein(a), apolipoprotein B100/A1 ratio, eGFR, blood urea nitrogen, hsCRP, white blood cell count, mean periodontal AL and the number of dental-caries-affected tooth surfaces (tooth decay).
They averaged the decline in health over time into a measure called the Pace of Aging. Using this, they created an epigenetic clock called DunedinPACE to estimate how quickly someone is aging.
“The way we age as we get older is quite distinct from how many times we’ve traveled around the sun,” said Ahmad Hariri on Science Daily, professor of psychology and neuroscience at Duke University.
Brain aging = biological aging?
In this new study, researchers used a single brain scan (T1-weighted MRI) taken when participants were 45 years old. They combined this with their DunedinPACE data to create a new measure called DunedinPACNI, based on brain imaging.
When they tested DunedinPACNI in other groups—like the Alzheimer’s Disease Neuroimaging Initiative, UK Biobank, and BrainLat—they found that people with faster DunedinPACNI scores were more likely to have cognitive decline, faster brain shrinkage, and develop dementia.
While the message in the headlines was that people with faster brain aging had worse cognitive, brain health, and higher risk of fragility, it’s much bigger than that.
With more studies, we may soon be at the point where a quick scan of the brain can tell us how fast we are aging. You can already buy the DundeninPACE blood test, but it’s pricey. [Save your money and download my biomarker guide for free]
In short, the Dunedin study is one-of-a-kind—it tracks aging changes and shows how important midlife is.
Our results, alongside the fast-growing literature on DunedinPACE, suggest that these unique design characteristics of the Dunedin Study make it a powerful training sample for longitudinal biomarkers of aging.
This isn’t ready for Primetime yet, but I’ll keep following these results and keep you informed.
The LE8 and midlife women
You may seen headlines like this one about sleep and midlife women’s health. No duh!
In menopause, sleep is vitally important for women’s long-term heart health, study finds
This was based on the SWAN study of women transitioning through menopause in the July issue of Menopause.
Researchers looked at changes to the American Heart Association’s Life Essential (LE) 8 (including diet, physical activity, nicotine exposure, sleep, BMI, lipids, glucose and blood pressure) at baseline and followup. They measured vascular health including carotid intima media thickness, pulse wave velocity, and carotid plaque presence along with CVD related events and deaths.
About 21 percent of women met all the LE8 criteria. For midlife women, blood pressure, blood sugar, smoking, and sleep were the four biggest LE8 affecting heart health.
Better sleep quality—either at the start or improving over time—was linked to a lower risk of heart problems, such as heart attacks, strokes, and even death.
Now here’s what gets me. Those vascular measures only examined the health of large arteries, even though women are at higher risk for coronary microvascular disease. Why can’t they throw in a measure to assess the microcirculation?
For more about this major issue in women’s health see my post: Women Have Been Misled About Heart Disease.
And of course, no mention of the quiet sleep thief in midlife women.
The threes to remember
Those estrogen charts you see on social media are not an accurate portrayal of what’s going on with estrogen during the lifespan.
We’re getting closer to measuring how fast people age midlife, and that’ll help us choose the right steps to take.
Even studies on midlife women and heart health aren’t recognizing the that women are more likely to get coronary microvascular disease (CMD) than coronary artery disease. That needs to change.
While I was writing this, the FDA had a big hearing about menopausal hormone therapy for menopause yesterday [July 17th]. I’ll be posting about this soon. In the meantime, you can watch the two-hour session here, and public comment will come in about a week.
Let me know what you think about all of this?
Thank you for this helpful information!