Women doing moderate-intensity running continuously may harm hormonal health—58% of female runners develop luteal phase defects. Four female experts reveal the optimal exercise protocol: brief high-intensity work (30 seconds maximum effort, 2-3 minute recovery, once weekly) combined with heavy strength training three times weekly and low-intensity movement prevents inflammation, preserves fertility, and protects brain health through lactate production. Building VO2 max requires only one high-intensity session weekly using the 4x4 protocol or 30-second sprint intervals with full recovery, not daily running.