Dr. Herman Weiss
Oct 15, 2026
Here is a number I think about often: two-thirds of people with dementia are women, and women carry roughly twice the lifetime risk. Researchers have suspected for years that perimenopause - the stormy hormonal transition of the mid-to-late forties - is one reason why. The obvious follow-up question: can exercise during that window protect the brain? Until now, no randomized trial had tested resistance training (weights, machines, bands) on cognition across the stages of menopause. The first one just landed.
The research. The SMART brain study (BMC Medicine, September 30) is a pilot sub-study of an assessor-blinded randomized trial from the University of Calgary. Forty women aged 45 to 60 - some in perimenopause, some in early postmenopause - were randomized to nine months of supervised, progressive resistance training twice a week, or to a wait-list control. Thirty-five of them (17 training, 18 control) volunteered for the brain sub-study, which measured cognition with the NIH Toolbox battery and brain blood-flow responses with functional near-infrared spectroscopy (fNIRS) - a light-based way of watching the prefrontal cortex work during a task.
What they found. The interesting result is not just that training helped - it is WHERE it helped, and when. Memory improved with training in the women who were still in perimenopause. Set-shifting - the mental flexibility to switch between tasks - improved with training in the women who were already past menopause. And the blood-flow response in the left dorsolateral prefrontal cortex (a hub for attention and working memory) increased with training only in the postmenopause group. In other words: the same exercise, two different reproductive stages, two different cognitive wins. The brain's window of responsiveness seems to move as hormones shift.
What you gain from this. If you are in your forties or fifties and keep forgetting why you walked into a room, this is one more concrete reason to pick up weights twice a week - not for your jeans, for your neurons. The intervention was realistic: supervised sessions, twice weekly, progressive. And the stage-specific finding is quietly hopeful: it suggests there is no single "too late" point. Perimenopause and early postmenopause each responded - just differently.
For my PMOS readers: this study was not about PMOS, and I am reading across, not quoting it. But many of you have lived with insulin resistance for decades, and muscle is your biggest glucose sink. If resistance training helps the midlife brain AND improves the metabolic terrain you already manage, that is two wins from the same habit. When you reach the perimenopause window, you will want this tool already in your routine.
Now the honest limits. This is a pilot: 35 women, one center, nine months. The statistically solid findings are the stage-by-group interactions, not a blanket "weights boost memory" claim. The control group waited rather than doing a sham exercise, so expectation effects are possible. fNIRS watches cortical blood flow, not deep brain structure, and blood flow is a proxy, not proof of protection against dementia. And nine months cannot tell us whether the benefit lasts or prevents anything decades later. The authors say the same: this is the case for a bigger trial, not a finished answer.
I still find it one of the more useful papers this year, because it turns "exercise is good for you" into something more precise: the midlife female brain is trainable, and its respond-to-exercise settings change across the menopause transition. Start where you are.
Dr. Herman Weiss
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