Dr. Stacy Sims, a sports scientist, advocates for distinct exercise recommendations for women, particularly those over 40, arguing that "women are not small men." She contends that women above this age should prioritize heavy lifting and "polarized" cardio (either intense sprints or gentle walking), as mainstream fitness advice, largely derived from male data, can lead to a "skinny fat" physique and brittle bones around perimenopause. This stance stems from the significant underrepresentation of women in exercise research, creating knowledge gaps. However, other experts like Laurel Beversdorf and Sarah Court criticize Sims' approach, viewing it as potentially limiting and perpetuating harmful narratives about women's bodies. Fitness coach Elizabeth Davies emphasizes the importance of adaptable training over rigid, stage-specific rules, especially when many individuals struggle to meet basic exercise guidelines.