Base training zone for Ironman, first 4 weeks prep training
Z1 - RECOVERY 60-65%, easy pace, feels nice & light
Z2 - Steady BASE TRAINING, 65-70% easy enough that you can still breath only through the nose
Z3 - TEMPO, 75-80% of max effort, fairly hard but sustainable pace 60-90mins!
Z4 - SUB threshold
Z5a - SUPER threshold