Why Women Over 35 Should Lift Heavy: Insights from an expert on Female Physiology

At CrossFit Golden Gate, we work with many women of all ages who want to feel strong, confident, and in control of their bodies. But one of the biggest myths we still hear is that women should stick to light weights or high-rep workouts as they get older.

Exercise physiologist Dr. Stacy Sims, a leading researcher on female physiology and performance, says the exact opposite. For women over 35, lifting heavy and doing resistance training is essential, not optional. Here’s why:

1. It Fights Muscle and Bone Loss

As estrogen naturally declines in your late 30s and 40s, the body loses some of its ability to maintain lean muscle and bone density. Heavy strength training sends a powerful signal to preserve both. It keeps muscles active, bones strong, and metabolism high, helping you stay lean, capable, and resilient for decades. Read more about the importance of the hormonal response here.

2. It Builds Power and Stability

Dr. Sims emphasizes power, not just strength. Quick, explosive lifts and resistance training protect the fast-twitch muscle fibers that keep you balanced, quick, and agile. This becomes more important as we age and want to stay injury-free and mobile.

3. It Improves Metabolism and Hormone Health

More muscle means better blood sugar control and higher insulin sensitivity, two keys to avoiding midlife weight gain. Strength training helps regulate hormones, manage stress, and improve body composition far more effectively than endless cardio sessions.

4. It Boosts Mood and Reduces Stress

Lifting heavy doesn’t just change your body, it changes your mindset. Strength training improves confidence, reduces anxiety, and helps moderate cortisol, the stress hormone that can spike during busy or transitional times in life.

5. The Bottom Line

“You don’t need more cardio—you need more strength.” — Dr. Stacy Sims

If you’re a woman over 35, resistance training, especially lifting heavy weights, is one of the most powerful tools you have to feel strong, energized, and balanced. At CrossFit Golden Gate, a woman owned gym, we’ve been teaching strength training in San Francisco for over 13 years. Our experienced coaches specialize personal training in San Francisco and group classes to help women who are new to lifting or ready to take their training to the next level.

Schedule a free consultation here.