September 22, 2026 · 11 MIN
Zone 2 Hydration: Fluid and Sodium Targets for Long Aerobic Sessions
Zone 2 sessions lasting 90–180 minutes require 400–700 ml/hr of fluid with 300–600 mg sodium/hr to maintain aerobic output and prevent the 5–8% cardiac drift caused by progressive dehydration. Optimizing hydration during low-intensity base work protects training quality and accelerates adaptation.
