Why Your Body Isn't Responding to Training: Anabolic Resistance in Perimenopause

You haven't lost your discipline. Your physiology has shifted. Here's what the research actually says, and what it means for how you move, recover, and feel.

At Areté, this is the focus of my Performance and Recovery service: understanding how perimenopause changes the way your body trains, recovers, and adapts.

If you're in your 40s and your training feels harder for less result, you're not imagining it. There is a well-documented physiological shift called anabolic resistance, a reduction in the muscle's ability to respond to exercise and protein, that develops as estrogen declines in perimenopause.

A review in the Proceedings of the Nutrition Society (Cambridge) found that women approaching and past menopause show a measurably diminished muscle protein synthesis response to both exercise and food [1].

"This isn't a willpower problem. Your muscles require a different stimulus to adapt, and that's a physiological fact, not a personal failing."

What this means practically: the moderate-volume, moderate-intensity training that built your fitness in your 30s may need to evolve. Research increasingly supports prioritizing higher-load resistance training and adequate protein intake (many studies suggest 1.6–2.2g per kg of body weight daily) to overcome anabolic resistance in midlife women.

Estrogen plays a regulatory role in the body's stress response system, specifically, how the hypothalamic-pituitary-adrenal (HPA) axis manages cortisol. As estrogen declines in perimenopause, this buffering weakens.

A longitudinal study (the Swiss Perimenopause Study) found that cortisol rises across the menopausal transition as estrogen and progesterone fall [2]. Separately, exercise physiology research confirms that moderate-to-high intensity training (roughly 60–80% of maximum effort) produces meaningful cortisol spikes, and for women whose HPA axis is already less regulated, the recovery cost of repeated high-intensity sessions may be higher than it once was.

This doesn't mean you should stop challenging yourself. It means recovery deserves to be treated as a serious training variable, not an afterthought.

A standard hemoglobin result (from a routine CBC) can look completely normal while your ferritin, the measure of stored iron, is low enough to impair your energy, recovery, and adaptation to training. At altitude, this gap matters even more.

Research published in the Journal of Applied Physiology found that athletes with insufficient iron stores had a diminished erythropoietic response to moderate altitude exposure compared with iron-replete athletes [3].

Progesterone has a well-documented role in regulating breathing during sleep, it stimulates the respiratory centers, raises the hypoxic ventilatory response (the drive to breathe when oxygen is low), and supports upper airway muscle tone. Research published in the American Journal of Respiratory and Critical Care Medicine found that hormone replacement therapy in postmenopausal women is associated with a lower prevalence of sleep-disordered breathing [4].

For women living at altitude, where the air is already lower in oxygen, this mechanism is physiologically relevant, though it has not yet been studied directly in perimenopausal women at elevation. If you've noticed your sleep quality worsening in a way that doesn't track with stress or lifestyle, this is worth raising with a provider who is familiar with both hormonal health and altitude physiology.