Short answer: a VO₂ max test tells you how big your engine is. A blood lactate test tells you how much of that engine you can use, and at what pace. If you train for a time goal, you'll get the most from doing both together.
The two tests get lumped together a lot, and people often book the wrong one for what they want to know. Here's what each test measures, what you walk away with and how to choose.
The Two Tests Side by Side
| VO₂ max test | Blood lactate test | |
|---|---|---|
| What it measures | The most oxygen your body can use during all-out exercise | How much lactate builds up in your blood as the pace rises |
| How it's done | A graded treadmill test to exhaustion, wearing a mask | A treadmill step test, with a small earlobe blood sample at each stage |
| Effort | Maximal: you finish completely spent | Hard but controlled: stages build steadily towards threshold |
| Key results | VO₂ max, peak heart rate, ventilatory thresholds (VT1, VT2) | Lactate curve, LT1 and LT2, as paces and heart rates |
| Training zones | Heart rate zones | Heart rate zones and exact paces |
| Price | £90 | £125 |
| Best for | Your fitness and health baseline, longevity, team sports | Endurance training and racing to a time goal |
Both together cost £175, which is £40 less than booking them separately.
What a VO₂ Max Test Tells You
VO₂ max is the ceiling of your aerobic fitness: the most oxygen your heart, lungs and muscles can deliver and use. It's measured in millilitres of oxygen per kilogram of body weight per minute (ml/kg/min).
It's one of the strongest markers of long-term health and of your potential in endurance sport. It also responds well to training, which makes it a useful number to track over time.
A VO₂ max test gives you:
- Your measured VO₂ max, and how it compares with people of your age and sex
- Your true peak heart rate, not a "220 minus age" guess
- Two breathing thresholds (VT1 and VT2), which we turn into personal heart rate zones
What it doesn't tell you is how long you can hold a given pace. Two people with the same VO₂ max can race very differently, which is where lactate comes in.
What a Blood Lactate Test Tells You
As you run faster, your muscles produce more lactate. At easy paces, your body clears it as fast as it's made. Past a certain point it builds up faster than you can clear it, and the pace soon becomes unsustainable.
A blood lactate test finds those turning points precisely:
- LT1: where lactate first starts to rise. Below this is true easy running, your real Zone 2.
- LT2: where lactate rises sharply. This is roughly the hardest pace you can hold for about an hour, and it's closely linked to race performance from 10K to marathon.
Because we measure the blood directly at each stage, you get your zones as exact paces as well as heart rates. You know what "easy" and "threshold" mean for you, not for an average runner.
Lactate thresholds also shift quickly with training, often faster than VO₂ max. That makes the test a sensitive way to check that your training is working.
Why You Might Want Both
Think of VO₂ max as the size of your engine and lactate threshold as how hard you can run it without overheating. Race performance depends on both.
Take two runners, each with a VO₂ max of 55 ml/kg/min (an illustrative example):
| Runner A | Runner B | |
|---|---|---|
| VO₂ max | 55 | 55 |
| LT2 as % of VO₂ max | 75% | 88% |
| What to work on | Threshold and tempo work to raise LT2 | Intervals at or near VO₂ max to raise the ceiling |
On paper they're equally fit, but Runner B will be faster over a half or a full marathon. They also need completely different training. Test only one number and you can't tell which runner you are.
That's why we recommend the combined test for runners and triathletes training for a time.
Which Test Should You Book?
| Your goal | Book |
|---|---|
| A marathon, half or triathlon time goal | VO₂ max + blood lactate (£175) |
| Exact training paces for running or cycling | Blood lactate (£125) |
| Checking your Zone 2 is really Zone 2 | Blood lactate (£125) |
| A health or longevity check | VO₂ max (£90) |
| A fitness baseline for football, HYROX or team sport | VO₂ max (£90) |
| Your first ever test, not sure what you need | VO₂ max + blood lactate (£175) |
If you're still unsure, message us before booking and we'll recommend one. For full prices and what happens on the day, see VO₂ Max Testing in Manchester & Cheshire: What It Costs and What You Get.
FAQs
Can I do both tests on the same day?
Yes. The combined test runs both in one visit. The lactate stages come first, then the test continues to your maximum for VO₂ max.
Is a lactate test better than a VO₂ max test?
Neither is better. They answer different questions. Lactate is more useful for setting training paces, and VO₂ max is more useful as a measure of overall fitness and health.
Can my watch tell me my lactate threshold?
It can estimate it from heart rate and pace, but it can't measure lactate. Estimates are often a long way off for individuals, which can put every training zone in the wrong place.
Does the blood sample hurt?
Hardly at all. We take a tiny drop from the earlobe, which most people find easier than a finger prick.
I'm not an elite athlete. Is this for me?
Yes. Most of the people we test are recreational runners, cyclists and gym-goers who want to train smarter or understand their fitness.
Book Your Test
Find out how big your engine is, how much of it you're using, and exactly how to train it. Testing takes place at our lab near Knutsford, Cheshire.
Book your performance testQuestions? Email perform@injuryandperformance.co.uk or message us on Instagram @perform.180
