Running & Athletics What is the 80 percent rule in running? March 6, 2026 by Mercier | Leave a Comment The 80 percent rule in running is a training principle that suggests keeping your heart rate at approximately 80% of your maximum heart rate during most of your runs. This approach aims to build aerobic capacity and endurance without overtraining, allowing for more consistent and sustainable progress in your running journey. Understanding the 80 Percent […] Read more ยป