45-Minute Zone 3 Continuous Pool Swim

Session Overview

This 45-minute continuous pool session sits in Zone 3 — comfortably uncomfortable. You are working above easy aerobic pace but below threshold. This builds significant aerobic capacity and teaches your body to sustain a strong swim pace for 750m to 1500m race efforts. Unlike interval sessions, there is nowhere to hide here.

Session Details

• Duration: 45 minutes total
• Location: 25m or 50m pool
• Target effort: Zone 3 — breathing hard but sustainable
• Pace benchmark: Approximately 10–15 seconds per 100m slower than CSS pace
• Estimated distance: 2,000–2,400m depending on pace

Warm-Up (10 minutes)

• 400m easy front crawl, building pace gradually over first 200m
• 4 × 50m with 15 seconds rest: 25m catch-up drills, 25m full stroke

Main Set (30 minutes)

• 1,500m continuous front crawl at Zone 3 effort — no stopping, no rest intervals
• Target a consistent pace throughout — do not blow up in the first 500m
• Breathe bilaterally every 3 strokes for the first 1,000m to regulate effort
• Final 500m: hold pace — if drifting, focus on catch mechanics, not harder kicking

Check-in points: At 500m and 1,000m, note how you feel. Zone 3 means you can say a few words but cannot hold a conversation. If you are speaking freely, increase pace. If you are gasping, ease back slightly.

Cool-Down (5 minutes)

• 200m very easy mixed strokes — backstroke, breaststroke, easy crawl
• Shake out arms at the pool wall before exiting

Coaching Notes

Zone 3 continuous swims are one of the most underused tools for triathletes who primarily do interval work. Your race-pace endurance — sustaining a hard effort for 20–40 minutes — is built right here. Aim to do this session once per week during the build phase. Track your distance covered in 30 minutes over a training block: a 100m improvement indicates real aerobic development.