Laura Norris Running

Here’s Why Your Easy Runs Slow Down During Marathon Training

During marathon training, runners often notice slower easy‑run paces, especially in peak weeks. This slowdown is usually a temporary "valley of fatigue" caused by accumulated stress from long runs and hard workouts, not a loss of fitness. Recovery of glycogen, muscle repair, and central fatigue can take 48‑72 hours, meaning easy runs performed shortly after hard sessions feel slower. Proper programming, adequate sleep, nutrition, and monitoring effort via heart rate or RPE help keep fatigue mild and prevent overtraining.