So what good are those long zone 2 training sessions doing?
This new review article claims that zone 2 is less effective than higher intensity training:
"We conclude that current evidence does not support Zone 2 training as the optimal intensity for improving mitochondrial or fatty acid oxidative capacity. Further, evidence sug- gests prioritizing higher exercise intensities (> Zone 2) is critical to maximize cardiometabolic health benefts, particularly in the context of lower training volumes."
TL;DR
Zone 2 compared to higher intensity training:
- inferior mitochondria development
- no better at fat oxidation capacity
- inferior at improving cardiovascular function
Link to the complete document.
Getting the popcorn ready.