12-week marathon plan for busy athletes: data-driven and realistic

If your schedule is full, the biggest marathon risk is not low volume. It is inconsistent load: one hard week, one missed week, then panic training.

A realistic 12-week plan starts with three quality anchors: one threshold session, one long run with controlled progression, and one strength-focused day. Everything else supports recovery and consistency.

Use Garmin recovery trends and Strava weekly load to decide when to push and when to absorb. If sleep drops and heart-rate drift rises, reduce intensity early instead of forcing hero sessions.

At CoachUpFit, we coach this way because elite outcomes come from repeatable weeks. The goal is to arrive at race day healthy, confident, and able to execute your pace plan under fatigue.