For decades, women were steered toward cardio as the primary tool for health, weight management, and longevity. Walk more, run more, cycle more. It wasn't bad advice. Cardiovascular exercise is genuinely important. But during perimenopause, a cardio-only approach leaves significant gaps — in bone health, metabolic function, and hormonal balance — that the research makes increasingly hard to ignore.
This isn't an argument against cardio. It's an argument for adding something most women haven't been encouraged to prioritize.
What Cardio Does — and Doesn't Do — for Bone
Impact-based aerobic exercise like running and hiking does provide some mechanical load to bone. But the forces involved are relatively low compared to what resistance training generates, and the stimulus is repetitive rather than varied. Bone adapts most strongly to novel, high-magnitude loads — exactly what lifting provides.
Two popular forms of cardio — cycling and swimming — offer essentially zero bone loading. They're excellent for cardiovascular fitness and joint-friendly recovery, but they won't protect your skeletal density during a period when estrogen decline is actively accelerating bone loss.
The ACSM position statement on physical activity and bone health identifies resistance training as a primary bone-protective modality, specifically because of its capacity to generate the kind of mechanical strain that signals bone remodeling.
The Metabolism Argument
Aerobic exercise burns calories effectively during the session. Resistance training does something more persistent: it elevates metabolic rate for 24–48 hours afterward through excess post-exercise oxygen consumption (EPOC), and — more importantly — it builds the tissue that drives resting metabolic rate.
Muscle is metabolically expensive. Every pound of lean muscle burns roughly three times as many calories at rest as an equivalent pound of fat. Women who include resistance training maintain lean mass during periods of weight loss far better than those relying on cardio alone. This matters especially during perimenopause, when visceral fat — the metabolically active kind that accumulates around the midsection — becomes more prevalent. Research shows visceral fat responds particularly well to resistance training, independent of weight loss.
Hormonal Profiles of Cardio vs. Lifting
The hormonal response to different types of exercise diverges in ways that matter during perimenopause. Prolonged moderate-intensity cardio — think 60+ minute steady-state sessions — can chronically elevate cortisol. For women whose HPA axis (the stress response system) is already more reactive due to declining estrogen, this sustained cortisol elevation can work against recovery, sleep, and lean mass maintenance.
Resistance training, by contrast, produces a more favorable anabolic hormonal profile: growth hormone, IGF-1, and testosterone (yes, women produce meaningful amounts) all rise acutely in response to lifting. These hormones drive tissue repair and maintenance that cardio alone doesn't stimulate to the same degree.
This Isn't Anti-Cardio
Walking is genuinely excellent — underrated, accessible, and associated with significant health benefits that compound over decades. Cardiovascular fitness is important for heart health, cognitive function, and longevity.
The point isn't to swap cardio for lifting. It's to recognize that if you've been doing one without the other, the evidence is pointing clearly toward what you should add. The combination of resistance training and cardiovascular exercise produces better outcomes — across bone density, body composition, metabolic health, and quality of life — than either alone.
For women who have limited time, the research suggests prioritizing resistance training over additional cardio volume. You can maintain cardiovascular health with 150 minutes of moderate activity per week (including low-intensity movement like walking). Getting strong requires something more intentional.