Calculate 5 heart rate zones from ventilatory thresholds

VO₂ max lab tests often give you your ventilatory thresholds. This calculator helps convert those thresholds into the five heart rate zones used by most fitness trackers.

Enter your ventilatory thresholds to see zones.

How does it work?

Zone 1 and Zone 2 are below VT1, Zone 3 and Zone 4 are above VT1 but below VT2, and Zone 5 is above VT2.

Expand to see the code that calculates the zones

// Zone 3 and Zone 4 are evenly split between VT1 and VT2
const zoneSize = Math.ceil((vt2 - vt1) / 2);

const zone1 = {
  top: vt1 - zoneSize,
};

const zone2 = {
  bottom: zone1.top + 1,
  top: vt1,
};

const zone3 = {
  bottom: vt1 + 1,
  top: vt1 + zoneSize,
};

const zone4 = {
  bottom: zone3.top + 1,
  top: vt2,
};

const zone5 = {
  bottom: vt2 + 1,
};

I hope it's clear that this isn't medical advice, just a fun tool that I wanted to make after getting my own VT results from Rutgers NEXT. Data isn't stored.