Zone 2 cardio
Uses itAbout four sessions a week, usually on a stationary bike with a power meter, holding finger-stick lactate around 1.8-1.9 mmol; treadmill at 15% incline/3.0-3.4 mph or elliptical as alternatives
In an AMA excerpt on his site, Attia described his own zone 2 practice and how he calibrates intensity with a lactate meter.
Source: Peter Attia on Zone 2 and Zone 5 Training (podcast, 8 Feb 2022)