Menopause Changes Your Metabolism. Cold and Heat Are Underused Tools.
What shifts when oestrogen falls, and why two of the oldest tools we have are the ones almost no one thinks to use.
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Menopause is not a malfunction. It is a transition, and like every transition in the body it changes the rules.
When oestrogen declines, several things shift at once. The cardiovascular protection oestrogen quietly provided fades. Thermoregulation becomes less stable, which is part of why hot flushes and night sweats appear. Sleep frays. Mood swings. And metabolism becomes less forgiving than it was a decade earlier.
Most of the conversation around this stops at hormones, or jumps straight to medication. I want to talk about two tools that are badly underused here, cold and heat, and I want to do it by showing you what the actual research found, not by making promises.
The cold water study that surprised even me
In 2024, a team led by researchers at UCL published a study in Post Reproductive Health [1]. They surveyed 1,114 women who regularly swim in cold water, 785 of them going through menopause, and asked in detail how it affected their symptoms.
I want to be precise about what this study is and is not, because that honesty is the whole point of this journal. It is a survey. It measures what women reported, not what was recorded in a lab. That means it cannot prove cause, and the women who join cold water communities may differ from those who do not. Take the numbers as strong signal, not as final proof.
With that said, the signal is striking. Among menopausal women, 46.9% reported reduced anxiety, 34.5% reduced mood swings, 31.1% improved low mood, and 30.3% reduced hot flushes, attributed to cold water swimming. The psychological symptoms, the ones that most erode quality of life, moved the most.
Why do I take this seriously despite it being survey data? Because it lines up with the physiology. We know cold produces a clean rise in alerting neurochemistry without a cortisol surge. We know regular exposure trains thermoregulation. A body re-learning to manage its own temperature is exactly what you would want during a transition where thermoregulation has destabilised. The mechanism and the reports point the same way. That convergence is what moves a finding from interesting to worth acting on.
The heat side, and why it matters more after menopause
Heat has the longer evidence trail, and it matters most precisely when oestrogen’s cardiovascular protection is gone.
The landmark work comes from Finland [2]. Researchers followed 2,315 middle-aged people for a median of more than twenty years, sorting them by how often they used a sauna. Compared with once a week, those using a sauna four to seven times a week had substantially lower rates of fatal cardiovascular disease and all-cause mortality over the follow-up.
Two honest caveats, because they matter. This cohort was men, so I extend it to women with appropriate caution. And it is an association study, not a trial, so it shows a strong, dose-dependent link rather than proof of cause. But the dose-response pattern, more sauna tracking with better outcomes, is the kind of pattern that makes physiologists lean in. And the timing logic is hard to ignore. After menopause, when the cardiovascular system loses a layer of hormonal protection, a well-supported cardiovascular training stimulus becomes more valuable, not less.
Where this goes deeper
Everything above is the why. In the companion piece for paid subscribers, I go much further into the evidence and the practice.
In the full piece you will get answers to:
What actually changes in your metabolism when oestrogen falls, beyond the symptoms you already feel
The later Finnish study that included women, and the mortality numbers it found
What the cold water survey can and cannot prove, read honestly rather than hyped
Why heat becomes the priority tool after menopause, not cold
How to use cold when your thermoregulation is already unstable, without making hot flushes worse
How to keep adjusting as your body moves through the transition
If you want the science taken seriously for women in this stage, that piece is where I do it.
Cold and Heat Through Menopause: The Science, and How to Practise It Well
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References
[1] Pound M, Massey H, Roseneil S, et al. How do women feel cold water swimming affects their menstrual and perimenopausal symptoms? Post Reproductive Health. 2024;30(1):11-27. doi:10.1177/20533691241227100
[2] Laukkanen T, Khan H, Zaccardi F, Laukkanen JA. Association between sauna bathing and fatal cardiovascular and all-cause mortality events. JAMA Internal Medicine. 2015;175(4):542-548. doi:10.1001/jamainternmed.2014.8187
