Zone 1 is commonly known as the recovery zone. We don’t think of it as a “training zone” like the rest of them. Usually zone 1 is described as “extremely easy”, “embarrassingly easy”, “gentle”, and “slow”. It’s basically one step above sitting on the couch. None of these words make us feel like we’re getting any work done so we tend to avoid zone 1 because it’s typical descriptors devalue its training worth.
In a study from the International Journal of Sports Physiology and Performance*, that compared training intensity distribution during the course of an Ironman season, statistically significant performance increases were shown when training time was spent primarily in zone 1, compared to zone 2 and higher. For the purpose of this study, zone 1 corresponds to heart rates below aerobic threshold, and zone 2 corresponds to heart rates at and above aerobic threshold (but below anaerobic threshold), which is the intensity in which an Ironman is primarily performed. The participants that spent the majority of their training time above their aerobic threshold (zone 2), had comparatively slower competition times than those who trained mostly below their aerobic threshold.
Read Laura’s complete article HERE