How many studies support Zone 2?

"Zone 2 training" (low-intensity aerobic exercise performed just below the first lactate/ventilatory threshold) has become a popular longevity concept, but the best current evidence is considerably more skeptical of the specific claim than the popular narrative suggests. That's backed by 7 published studies in Vitaebase's database, including 4 meta-analyses, the most recent from 2025 -- a modest but real research base.