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Your VO2 max is one of the best numbers you have for understanding your overall health—and the good news is that you can move it in the right direction. You don't need fancy equipment, hours of free time, or to already be in great shape. In fact, the less fit you are right now, the bigger the gains you can expect to see.
Here's what the evidence says about raising your VO2 max, and how to start.
What Is VO2 Max, and Why Does It Matter?
VO2 max is the most accurate way to measure your cardiorespiratory fitness (CRF)—basically, how well your heart, lungs, and muscles work together to use oxygen during exercise. (We cover the basics in this post.)
Why care about it? Because CRF is a strong predictor of how long you'll live—even stronger than traditional cardiovascular risk factors. It's also a better predictor of mortality and long-term health than your physical activity levels alone.1 That's because VO2 max reflects more than just how much you move; it also captures how your body responds to exercise and your underlying genetics.2
So the real question is: how do you improve it?
The Single Most Important Factor: Intensity
If you remember one thing, remember this: intensity matters most. As a rule of thumb, the harder the effort, the bigger the boost to your fitness—and you don't have to do much of it to benefit.
Just how much does intensity matter? Many physical activity guidelines treat 1 minute of vigorous activity as equivalent to 2 minutes of moderate activity. But a 2025 study of over 70,000 adults from the large UK Biobank cohort found that the trade-off is closer to 1 minute of vigorous activity to 4 minutes of moderate activity. They also found that it takes roughly 53 minutes of light activity to achieve the same benefits as 1 minute of vigorous activity.3 In other words, a little hard effort goes a long way.
With that in mind, here are the most effective ways to raise your VO2 max.
HIIT: The Most Effective Option
High-intensity interval training (HIIT) gets a lot of hype—and when it comes to VO2 max, it's earned. HIIT means repeated bouts of hard exercise (think 80% or more of your maximum heart rate, or working so hard you can only say a few words between breaths) broken up by periods of rest or easier effort. Intervals usually run 3 to 5 minutes, with similar recovery periods in between.
Compared with not exercising, HIIT improves VO2 max by about 5–6 mL/kg/min on average—or roughly 1.5 METs (a MET is a simple unit for measuring exercise intensity).4,5 To put that in real terms, for someone who already exercises that's like shaving 2 minutes off your 5K time. For others, it can be the difference between struggling to climb a flight of stairs and walking up it with groceries in hand. People who start from a sedentary baseline might gain an extra ~3 mL/kg/min on top of that.
What About Sprint Interval Training?
Sprint interval training (SIT) is a shorter, harder form of HIIT. Instead of 3–5 minute efforts, you go "all out"—a true 10/10 effort—for about 30 seconds, then rest for 3 to 5 minutes. A 6-week randomized controlled trial found that SIT improved VO2 max by almost 5 mL/kg/min compared with not exercising.6
Both HIIT and SIT work well, but current evidence gives HIIT a slight edge—about 1 mL/kg/min more than SIT.6,7 Notably, aerobic HIIT (done at a hard effort but not quite all-out for intervals of 2 minutes or longer) outperforms shorter sprint intervals. The likely reason: longer intervals at a high aerobic intensity keep your oxygen-transporting system under sustained strain, which drives improvements in stroke volume (the amount of blood your heart pumps per beat)—a key contributor to fitness.7,8
Examples of HIIT and SIT Workouts
- Long-interval HIIT (the "4x4 Norwegian Protocol"): 4 minutes at ~90–95% of your maximum heart rate or maximum effort, followed by 3 minutes of active recovery at ~60–70% of your maximum heart rate. Repeat 4 times, 3 times per week.8
- Sprint-interval training (SIT): 30 seconds at “all-out” effort, followed by 4 minutes of rest. Repeat 4–8 times, 3 times per week.9
Not a Fan of Intervals? Other Options Work Too
If HIIT isn't your thing, you still have great choices.
Endurance Training
Endurance training—also called moderate-intensity continuous training (MICT)—is steady aerobic exercise at a fairly stable pace, where your body is working but can still keep up. Think 30–60 minutes at about 65–80% of your max heart rate, where you can talk but not easily.
Continuous training can improve VO2 max by 4-5 mL/kg/min compared with not exercising.5,10 On average, the gains are a bit smaller than with HIIT—usually 1–2 mL/kg/min less, according to large reviews and meta-analyses.4,11
Effort still counts here: pushing to a harder pace (conversation is very difficult, heart rate 70-80% of your max) beats an easier pace (you can still chat, albeit with some difficulty).6
That said, even low-intensity work helps. A 2026 meta-analysis of 37 studies found that training entirely at lower effort levels (you can carry on a conversation and feel like you could sustain the effort for hours, known to some as “Zone 2”) improved VO2 max by 4.5 mL/kg/min compared to no exercise.12
Strength Training
Resistance, or strength, training isn't as powerful as cardio for VO2 max, but it does help—somewhere in the range of 1 to 3 mL/kg/min.13 The format matters: circuit-style training with short rests between exercises, using moves that work several muscle groups at once, tends to be most effective.14,15
Strength training works best when it’s paired with cardio—especially as you age. In a 4-year study of older men, those who lifted weights once a week with no aerobic exercise saw their VO2 max decline, while those who combined strength and cardio held steady or improved.16
How to Maximize Your Gains
Want to get the most out of your training? A 2024 scientific statement from the American Heart Association offers a blueprint:17
- Favor long intervals (2 minutes or more of hard work) over short ones.
- Build up total volume—aim for at least 15 minutes of high-intensity work per session.
- Stick with it. Studies of at least 4–12 weeks showed the largest benefits.
- Work up to 3 sessions of higher intensity exercise per week, ideally with a few days of easier activity mixed in.
The type of exercise can nudge results too: a 2026 meta-analysis of 28 controlled trials found that rowing- and cycling-based HIIT produced the biggest improvements in absolute VO2 max.11
“Yeah, but ….” Beating Common Roadblocks
Getting started is easier than you think–here’s some common misconceptions that tend to hold people back.
"I don't like running or cycling."
No problem. Intervals work with all kinds of movement—walking, jogging, running, cycling, swimming, rowing, and elliptical training all deliver similar benefits.17 Intensity matters more than modality.
"I don't have time."
Short sessions still work. Protocols with 5 minutes or less of high-intensity effort (for example, 3–6 rounds of 30–60 seconds at hard effort or more than 85% of your maximum heart rate) are time-efficient and produce meaningful VO2 max gains of 3.25–5.5 mL/kg/min.17
There's solid evidence that a workout taking 15 minutes or less total—warm-up and cooldown included—done at least 3 times a week for 6 weeks can improve VO2 max by about 3.5 mL/kg/min.18
Other quick, effective options include brief vigorous stair climbing,19 bodyweight workouts that mix cardio and resistance (sometimes called "high-intensity functional training"),20,21 and "exercise snacks"—very short bursts (under a minute) of vigorous activity sprinkled throughout your day.22
"I'm too out of shape."
That's actually good news—the less fit you are, the more you stand to gain. The best intensity depends on your starting point. For people who are previously inactive, even brisk walking for 30 minutes, 3-4 days a week can improve VO2 max by almost 10%.23
Is High-Intensity Exercise Safe?
For most people, yes—HIIT and SIT can generally be done safely, even with some health conditions, though medical supervision is sometimes needed.
Check with your clinician before starting a new program if you have known cardiovascular disease, a family history of sudden cardiac death, high blood pressure or diabetes that isn't well controlled, symptoms while exercising, or an active muscle or joint injury.24
Whenever you start something new or higher-impact, include a proper warm-up, allow for recovery, and ramp up gradually to avoid injury.25
The Bottom Line
Almost any exercise that gets your heart pumping and your breathing up will help your VO2 max. So pick something you enjoy and can stick with.
If you're just building an exercise habit, you'll see big returns from small amounts of higher-intensity work. If you're already fit, you'll need to challenge yourself harder to keep improving.
And if you have cardiovascular disease, risk factors, or symptoms during exercise, talk to a clinician first—especially before ramping up the intensity.
Quick Reference: HIIT Workout Parameters
A 2019 meta-analysis of 53 randomized controlled trials outlined the parameters for minimal and optimal VO2 max gains:26
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At NiaHealth, our mission is to make proactive health possible for all Canadians—by combining science with humanity. We believe that rigorous, evidence-informed health information should never feel out of reach. Every word we publish is intentional. We choose language that empowers rather than overwhelms, clarifies rather than complicates, and respects the lived experiences behind every health question. Learn more here.
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