Health⏱ 4 min read
How to Estimate VO2 Max from Resting Heart Rate
Lab VO2 max testing is expensive and inaccessible. The Uth-Sorensen formula uses only resting and maximum heart rate to give a surprisingly accurate estimate. Here is how to use it.
VO2 max is the gold standard measure of cardiovascular fitness, but testing it properly requires a lab, specialist equipment, and an exhaustive run-to-failure protocol. The good news is that a simple formula using resting and max heart rate gives results accurate to within about 5% for most people.
The Uth-Sorensen Formula
VO2 max = 15 x (Max Heart Rate / Resting Heart Rate)
Where:
Max Heart Rate (MHR): highest HR achieved during maximal exercise
Resting Heart Rate (RHR): measured first thing in the morning
before getting up, for 3+ days and averaged
Example: MHR 185 bpm, RHR 58 bpm
VO2 max = 15 x (185 / 58)
= 15 x 3.190
= 47.8 ml/kg/min
How to Measure Resting Heart Rate Accurately
Most accurate method:
1. Keep a fitness tracker or smart watch on during sleep
2. Read the "resting HR" or "overnight HR" figure
(averages HR during sleep -- more accurate than manual measurement)
Manual method:
1. After waking, lie still for 5 minutes
2. Take your pulse for 60 seconds (or 30 sec x 2)
3. Repeat on 3-5 mornings and average
Do NOT measure after coffee, alcohol, illness, or a stressful day.
RHR varies by 3-5 bpm between days -- averaging reduces noise.
Typical RHR by fitness level:
Elite athlete: 35-45 bpm
Very fit: 45-55 bpm
Average active adult: 55-70 bpm
Sedentary: 70-90 bpm
VO2 Max Interpretation Tables
CategoryMen (35-45)Women (35-45)Classification
Very poorBelow 33Below 27Sedentary
Poor33-3927-33Below average
Fair39-4633-39Average
Good46-5239-45Above average
Excellent52-5945-51Athletic
Superior59+51+Elite / very fit
Improving VO2 Max
VO2 max responds best to high-intensity training:
Zone 4-5 intervals (90-95% of max HR)
Most effective protocol: 4 x 4 minutes at 90-95% MHR, 3 min easy recovery
Research shows 8 weeks of this protocol can improve VO2 max by 5-10 ml/kg/min.
Also effective (lower intensity):
Long aerobic runs (Zone 2): builds cardiac stroke volume
Threshold runs (Zone 3-4): improves lactate clearance
For beginners: just starting consistent aerobic exercise
can improve VO2 max by 15-20% in the first 3-6 months.
The biggest gains come earliest; elite athletes improve by 1-2% per year.