By Dan Remon · Evidence checked October 2026
Every few years the fitness industry announces the death of cardio. High-intensity interval training was meant to finish it off.
It didn’t. Both work, they do different jobs, and the research comparing them is clearer than the arguments you’ll read online.
If you run a business, what you need to know is how little of each gets you the result, and how to fit it into a week that already belongs to other people. That’s what this covers.
HIIT vs cardio: which is better?
Neither wins outright. Meta-analyses comparing high-intensity interval training (HIIT) with steady, moderate cardio find that both improve fitness and both reduce body fat. HIIT improved VO2max a little more and, in one review, needed about 40% less training time. Fat loss was similar, or slightly better with intervals, depending on how it was measured. Steady cardio is the one you can do most days, and brisk walking counts. For a busy executive the answer is both: 2 short interval sessions a week, brisk walking on most days and 2 or 3 strength sessions. Most of these trials studied adults aged 18 to 45.
What counts as HIIT and what counts as steady cardio
HIIT means short, hard efforts with easy recovery between them, repeated a few times. The hard parts are vigorous. The CDC’s talk test puts it simply: at vigorous intensity you can’t say more than a few words without pausing for a breath.1 Sprint interval training is the shortest, hardest version, built on all-out efforts like the 20-second sprints in the study further down.
Steady cardio, which researchers call moderate-intensity continuous training and gyms often call LISS (low-intensity steady state), is a pace you hold without stopping. At moderate intensity you can talk, but not sing. Brisk walking at about 4 km/h (2.5 mph) or faster counts.1
Walking, cycling, rowing, paddling, trekking, golf on foot and playing with your kids all count, as long as you hold the pace. Pick the one you’ll actually repeat.
Easy cardio does draw a larger share of its fuel from fat while you’re doing it, which is where the fat-burning zone idea comes from. Fat loss is decided over weeks, and that’s what the trials below measured.
HIIT vs cardio for fitness (VO2max)
VO2max is the most oxygen your body can use during all-out exercise. It’s the standard measure of cardiorespiratory fitness and one of the most useful health markers you can track. I covered why in the corporate athlete.
A 2015 meta-analysis pooled 28 controlled trials with 723 healthy adults aged 18 to 45. Compared with no exercise, steady endurance training raised VO2max by 4.9 mL/kg/min and HIIT by 5.5 mL/kg/min. Both were large improvements. Head to head, HIIT came out ahead by a small margin of 1.2 mL/kg/min.2
The average participant was 25, so read the exact numbers with care if you’re 50. The direction is what I use: both build the engine, and intervals build it slightly more.
HIIT vs cardio for fat loss
A 2017 meta-analysis looked at 13 trials comparing HIIT with moderate continuous training in adults aged 18 to 45 with overweight or obesity. The programs averaged 10 weeks of 3 sessions a week. Both cut whole-body fat mass and waist size. There were no significant differences between them on any measure of body composition, but HIIT took about 40% less training time.3
A larger 2019 meta-analysis of 36 studies found the same for body fat percentage: both fell by about 1.5 percentage points, with no difference between the methods. Interval training did reduce total fat mass by 28.5% more. On average, the interval groups lost about 1.6 kg of fat and the moderate groups about 1.1 kg.4
Look at the size of those numbers. About a kilo of fat from a training program alone, and in the 2017 review body weight didn’t change. That’s why I never sell exercise as the fat-loss plan on its own. Food sets the deficit. Training keeps your muscle while you lose the fat, which I cover in adaptive metabolism. For the full plan on a tight schedule, read effective weight loss for busy executives.
Is HIIT harder to stick with?
HIIT has a reputation for making people quit. It’s uncomfortable, it’s easy to overdo, and too much too soon is the fastest way to start resenting your training.
The research points somewhere more useful. A 2019 meta-analysis pooled 67 HIIT programs from 55 studies with 1,318 previously sedentary adults. The average dropout rate was 17.6%. How hard people trained wasn’t related to dropout. Longer sessions and more training time per week were. Dropout was also lower in cycling-based programs than in running or walking ones.5
So keep it short, and cap it. 2 interval sessions a week is plenty, on non-consecutive days. If you’re new to it, start on a bike. On a week of bad sleep, long-haul flights or a heavy board cycle, swap them for easy sessions. Hard training is load, and so is that week. I cover the balance in stress management for executives.
The minimum effective dose for cardio
Minimum effective dose is the smallest input that produces the result you want. Anything above it costs time and recovery without buying you more. I wrote about the principle in why you need a minimum effective dose. Here it is applied to cardio.
A small 2016 trial at McMaster University in Canada showed how low the dose can go. 25 sedentary men with an average age of 27 were matched into sprint interval training, steady cycling or no training, and the 2 training groups trained 3 times a week for 12 weeks. The sprint session lasted 10 minutes and held 1 minute of hard work: 3 all-out 20-second sprints with 2 minutes of easy cycling between them, plus a warm-up and cool-down. The steady session was 45 minutes at about 70% of maximum heart rate, 50 minutes in all. Fitness rose 19% in both training groups, and insulin sensitivity improved similarly.6
It was a small group of men on bikes in a lab, so I don’t treat it as the final word. It does show the principle: on those markers, 1 minute of hard work did what 45 minutes of steady work did.
This is how I set the dose with clients:
- Name the outcome. Fitness, fat loss or a health marker. The dose depends on what you’re trying to move.
- Start with the least you’ll do on a bad week. A plan that only runs on good weeks stalls on the first bad one.
- Hold it for a 28-day cycle. Track one repeatable number: your resting heart rate on waking, or your time and heart rate over the same route at the same effort.
- Add only when the number stalls. One change at a time, so you know what caused the result.
Mine, to stay lean and keep my strength, is 3 strength sessions of 20 minutes and 2 interval sessions of 5 minutes a week. Yours will be different, and you find it by testing it.
A weekly cardio plan for busy executives
The WHO guideline for adults is 150 to 300 minutes of moderate activity, or 75 to 150 minutes of vigorous activity, or an equivalent mix, each week. It adds muscle-strengthening work on 2 or more days.7 This week meets it with 1 to 2 hours of dedicated training, plus walking you fit around your work.
- 2 interval sessions, 10 to 15 minutes each. Non-consecutive days, on a bike, a rower or a steep hill. The McMaster protocol is a good template: 2 minutes easy, 3 all-out 20-second efforts with 2 minutes easy between them, then 3 minutes easy. For the first few weeks, go hard rather than all-out.
- 2 to 3 strength sessions, 20 to 30 minutes each. 2 is the minimum I set, and 3 works best for most people. Most HIIT vs cardio arguments leave this part out, and it’s the part that keeps your muscle.
- Brisk walking, 30 minutes on at least 5 days. That alone covers the WHO’s 150 moderate minutes. Take calls on foot, walk to lunch, hold one-to-one meetings walking and use the stairs. A podcast or a colleague makes the time go faster.
- 1 longer easy session at the weekend, if you enjoy it. A ride, a hike, a paddle or 18 holes on foot.
If you have a heart condition, or you haven’t trained in a long time, get cleared by your doctor before you start interval training.
On the road, the plan shrinks rather than disappears: 10 minutes of intervals in a hotel gym or on the stairs, and a walk through the city.
The last filter is enjoyment. What you enjoy, you repeat, and what you repeat is what compounds. If you hate running, don’t run. The system survives the version of you that’s tired.
How to start
Find out where your week is leaking first, then install one change at a time.
- The 1% Scorecard. 8 questions, 2 minutes, free. You get a score out of 100 and the one thing to install first.
- The Quest. My performance membership, run in 28-day cycles. Your minimum effective dose for training, set and then held one change per cycle, with a structure that keeps running on the weeks you don’t feel like it. Cancel anytime.
If you want a plan built 1:1 around your calendar and your travel, Stealth Coaching starts with a Stealth Strategy Call.
Related reading: Fitness over 40: keep it simple, 17 reasons you’re not achieving your fitness goals and Find your body mechanic: why a physio belongs on your team.
FAQ
Is HIIT better than cardio for fat loss?
Not by much. In a 2017 meta-analysis of 13 trials, HIIT and moderate cardio reduced body fat by similar amounts, but HIIT took about 40% less training time. A 2019 meta-analysis found intervals cut 28.5% more fat mass, which averaged out at about 1.6 kg against 1.1 kg.
How many times a week should you do HIIT?
2 sessions a week, on non-consecutive days, is the cap I set for busy clients. Most trials in the meta-analyses used 3 sessions a week. With brisk walking on most days and 2 or 3 strength sessions, 2 short interval sessions fit inside the WHO weekly guideline.
How long should a HIIT workout be?
10 to 15 minutes including the warm-up is enough to start. In a 12-week trial, a 10-minute session with 1 minute of all-out effort raised fitness as much as 50 minutes of steady cycling. In a meta-analysis of HIIT programs, longer sessions predicted more dropout.
Is walking enough cardio?
Brisk walking counts as moderate-intensity activity, and the WHO recommends 150 to 300 minutes of moderate activity a week for adults. 30 minutes on 5 days covers the minimum. Add 2 short interval sessions if you want to raise your fitness further.
Sources
- Centers for Disease Control and Prevention. (2025). How to measure physical activity intensity. cdc.gov/
physical-activity-basics/ measuring/ index.html - Milanović, Z., Sporiš, G., & Weston, M. (2015). Effectiveness of high-intensity interval training (HIT) and continuous endurance training for VO2max improvements: A systematic review and meta-analysis of controlled trials. Sports Medicine, 45(10), 1469-1481. doi.org/10.1007/s40279-015-0365-0
- Wewege, M., van den Berg, R., Ward, R. E., & Keech, A. (2017). The effects of high-intensity interval training vs. moderate-intensity continuous training on body composition in overweight and obese adults: A systematic review and meta-analysis. Obesity Reviews, 18(6), 635-646. doi.org/10.1111/obr.12532
- Viana, R. B., Naves, J. P. A., Coswig, V. S., et al. (2019). Is interval training the magic bullet for fat loss? A systematic review and meta-analysis comparing moderate-intensity continuous training with high-intensity interval training (HIIT). British Journal of Sports Medicine, 53(10), 655-664. doi.org/
10.1136/ bjsports-2018-099928 - Reljic, D., Lampe, D., Wolf, F., Zopf, Y., Herrmann, H. J., & Fischer, J. (2019). Prevalence and predictors of dropout from high-intensity interval training in sedentary individuals: A meta-analysis. Scandinavian Journal of Medicine & Science in Sports, 29(9), 1288-1304. doi.org/10.1111/sms.13452
- Gillen, J. B., Martin, B. J., MacInnis, M. J., Skelly, L. E., Tarnopolsky, M. A., & Gibala, M. J. (2016). Twelve weeks of sprint interval training improves indices of cardiometabolic health similar to traditional endurance training despite a five-fold lower exercise volume and time commitment. PLoS One, 11(4), e0154075. doi.org/
10.1371/ journal.pone.0154075 - Bull, F. C., Al-Ansari, S. S., Biddle, S., et al. (2020). World Health Organization 2020 guidelines on physical activity and sedentary behaviour. British Journal of Sports Medicine, 54(24), 1451-1462. doi.org/
10.1136/ bjsports-2020-102955
This article is general information, not medical advice.
