Easy Zone 2 Run: 45-Minute Aerobic Base Session

Session Overview

Easy zone 2 running is the foundation of triathlon fitness. Despite feeling deceptively simple, consistent zone 2 aerobic work builds mitochondrial density, improves fat oxidation and increases your ability to sustain higher paces without accumulating lactate. This 45-minute session is ideal for recovery days, light training days or as a second run in a training week when your legs need to move without additional stress.

• Duration: 45 minutes
• Effort: Zone 1–2 (you can hold a full conversation throughout)
• Heart rate target: 60–75% of max HR
• Pace: No pace target — go by feel

The Run

• 0–5 min: Walk or very easy jog to warm up. Let your heart rate rise gradually.
• 5–40 min: Easy, conversational running. Stay in zone 2. If you find yourself going faster because it feels easy, slow down deliberately. The goal is aerobic development, not speed.
• 40–45 min: Walk or slow jog to cool down. Shake out the legs.

Coach’s Notes

Most triathletes run their easy days too hard. If you feel like you are going embarrassingly slowly, you are probably in the right zone. Use the talk test: if you cannot maintain a full sentence without pausing for breath, slow down. Over time, your easy pace will naturally improve as your aerobic system develops — but this only happens if you stay genuinely easy. A heart rate monitor is useful here to keep you honest. This session is also excellent the day after a long ride or hard swim, as it keeps the legs moving without adding meaningful fatigue.