Book Review: Next Level by Dr. Stacey Sims

Several months ago, I reviewed Dr. Stacey Sims’ book Roar, which focuses on how women’s physiology influences training, nutrition, and recovery across the lifespan. That review highlighted how understanding female biology can lead to more effective and sustainable fitness strategies. Next Level continues this work and expands it into the specific context of perimenopause and menopause, a stage of life that brings its own distinct physiological patterns and training considerations. The book is written for women who want to stay strong, healthy, and physically capable as they move through midlife and beyond.

Roar introduced the importance of recognizing hormonal rhythms and how they affect performance, recovery, and fueling. Next Level extends that framework into a phase of life where hormone patterns shift and eventually stabilize at new levels. Rather than focusing on monthly cycles, Next Level explores how longer-term hormonal changes influence metabolism, muscle, bone, sleep, stress, and training response. It provides practical guidance for women whose bodies feel different from earlier years and who want their training to reflect those changes.

Understanding midlife physiology

Dr. Sims explains what happens to metabolism, muscle mass, bone density, connective tissue, and nervous system regulation during perimenopause and menopause. She describes why training response, recovery patterns, and body composition often change during this period. The emphasis is on recognizing these shifts as part of normal physiology and adjusting training accordingly.

Cardio, intensity, and metabolic health

The book explores how different forms of cardiovascular training affect midlife physiology. Dr. Sims highlights the role of intensity, power, and varied training stimuli in supporting metabolic health, cardiovascular function, and physical performance. This perspective aligns closely with longevity-based programming that includes both aerobic conditioning and higher-intensity movement.

Strength, power, and protein

Next Level places strong emphasis on heavy compound lifting, progressive resistance training, and power-based movements as central components of midlife fitness and for preservation of muscle and bone density. Dr. Sims also discusses the importance of sufficient protein intake to support muscle maintenance, bone health, and metabolic resilience. These elements contribute directly to long-term physical independence and functional capacity.

Recovery, sleep, and stress regulation

The book includes thoughtful discussion of sleep quality, nervous system regulation, stress physiology, and recovery capacity. These factors play a meaningful role in how women adapt to training during midlife. Dr. Sims presents recovery as an active part of training rather than something separate from it.

Who Next Level Is For

This book is well suited for:

• Women aged 40+

• Women experiencing perimenopause or menopause

• Coaches and trainers working with midlife women

• Anyone interested in evidence-based longevity fitness

It is especially valuable for women who want training guidance that reflects how their bodies function during this stage of life.

Final Thoughts

Next Level offers a clear, practical, and research-informed guide for training during midlife. It builds on Dr. Sims’ long-standing work in female physiology and applies it directly to strength, power, cardio, recovery, and overall health. Together, Roar and Next Level form a comprehensive resource for women who want to stay strong, capable, and physically confident throughout the lifespan. For anyone interested in longevity fitness for women, Dr. Sims remains one of the most reliable and influential voices in the field.

Dr. Sims is one of my favorite researchers in the fitness and longevity space and someone I rely on often when designing training programs, especially for women. Her ability to translate complex physiology into clear, practical guidance is exceptional. Many of the strategies I use with female clients are informed by her work, particularly around strength training, aerobic conditioning, fueling, and recovery. Her research consistently supports approaches that are grounded in science and applicable to real life.