Drstacysims

It is the title of her TED Talk and the central argument behind all of her research: women have fundamentally different physiology, hormones, and training needs from men, and applying male-centric sports science to female athletes produces poor outcomes. Decades of exercise and nutrition research was conducted almost exclusively on men, and Dr. Sims has built her career on closing that gap with female-specific guidelines.

ROAR is a training and nutrition guide built around the female hormonal cycle, teaching women how to sync workouts, fueling, and recovery to each phase of their menstrual cycle. Dr. Sims argues this approach can dramatically improve performance, energy, and body composition compared to following generic plans designed around male physiology.

NEXT LEVEL focuses specifically on perimenopause and menopause, explaining how the hormonal shifts of that life stage change the way women should train and eat. Dr. Sims makes the case that heavy strength training and high-intensity work become more important — not less — as women enter menopause, directly challenging mainstream advice to slow down.

An ergogenic aid is anything that enhances athletic performance, and Dr. Sims argues that when women understand and train with their hormonal cycle rather than against it, the natural fluctuations — particularly the low-hormone follicular phase — can be used strategically to hit peak training loads. Rather than treating menstruation as a performance obstacle, she reframes it as a built-in roadmap for periodizing training.

Dr. Sims connects this common complaint to hormonal shifts — particularly the decline in progesterone and estrogen during perimenopause and menopause — which disrupt sleep architecture and raise core body temperature in the early morning hours. She also points to cortisol dysregulation and differences in female circadian biology as contributing factors, and her content stresses that fixing it requires more than standard sleep hygiene advice.

Dr. Sims explains that women's internal clocks tend to run on a slightly shorter cycle than men's, meaning they naturally incline toward earlier sleep and earlier waking. She argues this means women need to front-load behaviors like morning light exposure from the very start of the day, rather than simply copying male-oriented chronobiology recommendations.

Dr. Sims holds a PhD in exercise physiology and nutrition science and conducted postdoctoral research at Stanford University before building her public platform. She is a published researcher, the author of two books, and a keynote speaker at elite sporting and medical conferences — her YouTube and Instagram presence grew out of that scientific work, not the reverse.

She is a vocal advocate for heavy compound lifting during and after menopause, arguing it is one of the most effective tools women have to counteract muscle loss, bone density decline, and the metabolic changes tied to falling estrogen. Her #strongnotskinny messaging reflects this directly, and she pushes back hard against the prevailing idea that midlife women should scale exercise intensity down.

Yes, her TED Talk is titled 'Women are Not Small Men' and has become one of the most widely shared pieces of content she has produced. It summarizes her core argument that female athletes have been underserved by sports science because research has historically excluded women, and it laid the foundation for the global community she has built around female physiology and performance.

Dr. Stacy Sims is based in New Zealand, though the majority of her audience is in the United States and United Kingdom. She travels internationally as a keynote speaker, which has helped her reach well beyond her home country and build a following across YouTube and Instagram that spans multiple continents.