When two coaches say Zone 2, do they mean the same intensity?

Iñigo San MillánPhD · applied exercise physiologist, University of Colorado School of Medicine

Zone 2 sits AT the first threshold, and it is where you want most of your volume.

What it rests onHis own translation table: 'Moderate intensity domain: Zone 2, metabolic equilibrium: at LT1/VT1... This is the highest intensity at which the system is in true balance.' Zone 1 is below LT1, 'the system operates well within its capacity'. His Zones 3 to 4, which he calls metabolic drift, span from above LT1 up to CP, MLSS, FTP, VT2 or LT2, where blood lactate can look stable while 'the apparent stability of blood lactate masks a continuously deteriorating internal environment'.

Stephen SeilerPhD · exercise physiologist · Professor, University of Agder

Zone 2 is the region BETWEEN the two thresholds, and it is the region to minimise.

What it rests onIn the three-zone research model he works in, Zone 1 is everything below LT1 and Zone 2 is the LT1 to LT2 band, the region his work identifies as the one athletes drift into and should not live in. His own published point is the general form of this problem: dozens of intensity scales define between three and ten zones, the same number means different intensities in different scales, and only the two turn points are physiologically anchored while the subdivisions between them are arbitrary.