Female-Specific Exercise & Nutrition Protocols with Dr. Stacy Sims

Exercise physiologist Dr. Stacy Sims joins the Huberman Lab podcast for an in-depth conversation on how women's training and nutrition needs differ fundamentally from men's — and what protocols actually work at every life stage.

The headline finding: intermittent fasting and fasted training are detrimental for most active women. Women have more oxidative muscle fibers, making them already more metabolically flexible than men. Fasting raises baseline cortisol, disrupts kisspeptin neurons in the hypothalamus (women have two populations vs. one in men), and within just four days causes thyroid dysregulation and altered luteinizing hormone pulses. The fix is simple: 15g protein before strength training, add 30g carbs before cardio — just enough to signal the brain that fuel is available.

Post-training, women have a tighter recovery window than men (60 minutes vs. up to 3 hours). Reproductive-age women need ~35g protein within 45 minutes; perimenopausal and postmenopausal women need 40-60g due to increased anabolic resistance.

For resistance training, younger women should train to failure to build strength and hypertrophy. As women enter perimenopause (mid-40s), the emphasis should shift to heavy lifting with reps in reserve — focusing on strength and power rather than hypertrophy, because this drives central nervous system adaptations critical for longevity, proprioception, and cognitive health.

Dr. Sims warns against moderate-intensity cardio classes (Orange Theory, F45, Soul Cycle) for perimenopausal women: they drive cortisol up but aren't intense enough to trigger the post-exercise growth hormone and testosterone responses needed to bring cortisol back down. Instead, women should polarize training — true high-intensity intervals (80%+ for 1-4 minutes or full sprint for 30 seconds) paired with easy recovery work, avoiding the moderate middle ground.

The conversation also covers cold exposure (women should use cold water immersion of 1-3 minutes rather than long deliberate cold exposure due to differences in vasoconstriction), creatine supplementation (3-5g daily benefits brain health, mood, lean mass, and bone — especially important for women who get almost none from diet), and how training should adapt across the menstrual cycle.