Long Sunday Run: 2-Hour Aerobic Base Builder

Session Overview

A 2-hour easy long run designed to build aerobic base and fat-burning efficiency — the cornerstone of any long-course triathlon programme. This session is all about time on feet at a conversational pace, reinforcing efficient running form and preparing your body for back-to-back training days without accumulating excessive fatigue.

What You’ll Need

• GPS watch to monitor pace and heart rate
• Running shoes suitable for road or trail
• Hydration vest or handheld bottle — 2 hours requires active hydration
• Energy gel or 30-40g carbohydrate snack for fuel from 60 minutes onward

Warm-Up (10 minutes)

Begin the first 10 minutes at a very easy jog — RPE 3, well below your aerobic threshold. Let your body temperature rise naturally and resist the urge to push the pace early. This gradual build prevents injury and ensures you can sustain effort across the full 2 hours.

Main Set

Run continuously at Zone 2 / RPE 4-5 throughout. You should be able to hold a full conversation at all times — if you can’t, slow down. Take a gel or 30g of carbohydrates at 60 minutes and again at 90 minutes to practise race-day fuelling habits during long runs.

• Minutes 0-10: Very easy warm-up jog, RPE 3
• Minutes 10-90: Steady Zone 2 aerobic run, RPE 4-5, conversational pace throughout
• Minutes 90-110: Maintain Zone 2 — allow for slight HR drift as natural fatigue accumulates
• Minutes 110-120: Wind down to easy jog, RPE 3-4, begin cooling process

Cool-Down (5 minutes)

Reduce to a walk for the final 5 minutes. Stretch your calves, hip flexors, and hamstrings while they’re still warm. Prioritise nutrition within 30 minutes — aim for 40-60g carbohydrates and 20-25g protein to begin the recovery process and prepare for tomorrow’s training.

Coaching Notes

• The long run should feel like the easiest session of your week intensity-wise — duration is the training stimulus, not pace
• If building from shorter long runs, don’t increase duration by more than 15 minutes per week
• For beginners: reduce to 75-90 minutes and build gradually — running 2 hours too soon risks injury
• Heart rate drift is normal over 2 hours — monitor effort by feel, not just by pace