Training for a row marathon using heart rate zones (with an approximate MHR from the 500m base) with limited time (2 x 45 to 60-minute rows per week) provides several specific and strategic benefits—especially for beginners or busy individuals. Here's why this approach works:

1. Builds Aerobic Efficiency Safely

• Zone 2 training (your base zone) strengthens your cardiovascular system and teaches your body to burn fat for fuel.
• It improves mitochondrial density and capillary growth, which are crucial for endurance.

2. Reduces Risk of Injury‍

• By keeping most sessions in low intensity (Z2), you avoid the high stress that comes from always rowing fast.
• Perfect for those rowing just twice a week—less wear and tear.

3. Maximizes Training with Limited Time

• HR zones ensure you're getting the right physiological effect from each session—even with only 2 - 3 hours/week.
• You avoid wasting time rowing too hard or too easy without knowing the purpose.

4. Improves Fatigue Resistance

• Rowing consistently in Z2 teaches your body to sustain effort over long periods—a key requirement for row marathon success.

5. Structured Progression Through Z3/Z4

• Introducing Z3 tempo and Z4 intervals later helps improve your lactate threshold, making marathon pace feel easier.
• Done in small, structured doses to minimize overload on the heart.

6. Personalized & Scalable

• Training by heart rate adapts to your personal fitness level, not just pace.
• As you get fitter, your pace at each HR zone improves—so you see clear progress without needing to constantly retest or change targets.

7. Enhances Recovery & Monitoring

• HR helps you detect fatigue, overtraining, or illness early. If your HR is unusually high at an easy pace, it’s a sign to back off.

The Bottom Line

Heart rate zone training with a time-efficient structure helps beginners:

• Build endurance smartly
• Minimize injury
• Maximize performance gains
• Develop discipline for row marathon pacing