Zone 2 is everywhere, but where it sits differs a lot between people. Why fixed heart-rate percentages misclassify many athletes, and how lab tests, lactate, the talk test and HRV-based methods compare.
Winter pushes most long rides indoors, and few triathletes will sit on a trainer for four hours. What durability research says about shorter, harder indoor sessions, what they can't replicate, and how to plan the winter.
Many riders hold fewer watts on the trainer than on the road. What indoor-versus-outdoor studies show, why still air and heat matter most, how accurate smart trainers are, and how to set up a cooler indoor ride.
Myth: Zone 2 is simply a set percentage of your maximum heart rate.
Myth: Polarised training is clearly better than any other way to spread intensity.
Myth: If you can't hold your outdoor watts on the turbo, you've lost fitness.