If you want to maximize your fat loss, you need to spend less time doing cardio. It may seem counterintuitive, but you’ll burn more fat and get better results in a shorter amount of time.
That’s right: your 45-minute elliptical and treadmill sessions are wasting your time and shortchanging your fat loss results.
The best cardio for burning fat and preserving lean muscle is high-intensity interval training. HIIT workouts consist of short, high-intensity sprints mixed with low-intensity recovery periods.
For example:
- Warm up jog for 3 minutes
- Sprint hard for 30 seconds
- Easy walk for 60 seconds
- Repeat sprint/walk for 12 rounds
Total workout time: 21 minutes.
Why HIIT is superior to steady-state cardio
Extreme time efficiency isn’t the only advantage of high-intensity interval training.
- HIIT burns more fat. A lot more. For the same amount of calories burned, HIIT burns nine times more fat than steady-state cardio.
- Repeated sprinting causes spikes in human growth hormone (HGH), which helps your body burn fat long after you stop exercising. HGH plays an important role in mobilizing fat cells to be burned for energy.
- HIIT can raise your metabolic rate for 24+ hours after you stop exercising (sometimes called the “afterburn.”) This means you’re burning more calories at rest, and those calories are likely coming from your fat stores. You don’t get this with long runs.
- High-intensity sprints preserve muscle mass. Moderate-intensity cardio doesn’t. It’s been said that strength training and cardio training are enemies. And there is truth to this. But short bursts of all-out effort mixed with low-intensity recovery intervals will preserve muscle mass instead of breaking it down.
- The anaerobic conditioning you experience during HIIT also improves your aerobic capacity. But when you’re just training aerobically (like during longer runs and rides), there is no benefit to the anaerobic system. Translation: high-intensity anaerobic conditioning will get you into better cardiovascular shape.
- HIIT improves insulin sensitivity. This means that your body will tolerate more carbs and be less likely to store them as fat. Leaner, anaerobically trained people tend to have better insulin sensitivity.
But what about the ‘fat burning zone?’
A lot of cardio machines show a graph representing the ‘cardio training zone’ and the ‘fat burning zone.’ If you keep your intensity low enough, you’ll be in the fat burning zone.
This is not technically wrong, but it’s kind of a sham.
During low intensity exercise, fat is the dominant fuel source. When you’re sitting on your ass or sleeping, fat is the dominant fuel source. But you’re burning such a small amount that you probably won’t see a difference in your body composition.
When you work out at higher intensity, (i.e. sprinting) fat is no longer the dominant fuel source; carbohydrate is. But you’re burning a lot more total energy. So even though fat is a lower percentage of energy burned, you’re burning more total fat.
And you will continue to burn more fat throughout the day, because it takes a lot of energy to recover from a hard sprint workout — and that energy comes from fat.
You knew the fat burning zone was too good to be true. Nobody ever got ripped by strolling on a treadmill for 45 minutes.
What’s wrong with regular cardio?
There’s nothing bad about steady-state cardio. Sometimes you just want to go for a run to clear your head or scan for eye candy. It’s a hell of a lot better than sitting on the couch.
But if you’re looking to burn the maximum amount of fat in the shortest time, steady-state is not what you want. Unless you are training for a marathon or 10K, there’s no reason for you to be doing long, steady-state cardio instead of high-intensity sprints.
Three HIIT workouts to get you ripped
You can adjust these numbers to fit your needs. Just don’t stray too far off the plan — the workout still needs to kick your ass.
HIIT Workout #1: Treadmill Sprints
This is a basic sprint/walk workout. It’s brutal and it never gets old.
- Set the incline to 2.0 and warm up jog at 5-6 mph for 3-5 minutes
- Sprint at 8-10 mph for 30 seconds
- Walk at 3.5 mph for 60 seconds (90 sec for beginners)
- Repeat sprint walk for 10-12 rounds…try not to exceed 25 minutes total
HIIT Workout #2: Bike Speed and Resistance
This workout contains two types of sprints. Five speed sprints and five hill (i.e. resistance) sprints.
- Warmup: pedal at 80 rpm on low resistance for 3-5 minutes
- Set medium resistance and pedal 120+ rpm for 30 seconds
- Set low resistance and pedal at 60-70 rpm for 60 seconds
- Repeat for 5 rounds, then…
- Pedal at 70 rpm at the highest resistance possible — this is a strength interval so really push yourself — 30 seconds
- Set low resistance and ride easy for 90 seconds
- Repeat for 5 rounds. You might want to finish with a 3-5 minute easy ride to increase blood flow and aid in recovery
HIIT Workout #3: Treadmill Incline
This workout is lower impact on the joints because it doesn’t require a lot of running speed. But don’t be fooled; it will still destroy you metabolically.
- Warmup: walk at 3.5 mph on a 3.5 incline for 3 minutes
- High interval: run at 5-6 mph on a 6.5-8.0 incline for 30 seconds
- Low interval: walk at 2.5-3 mph on a 3.0 incline for 60 seconds
- 10-12 rounds
- There will be some transition time as the ramp incline adjusts — this should happen during the rest interval. In other words, make sure the ramp is all the way up before you start counting your 30-second sprint.
Keep it short, sweet and sweaty
You can be creative with your HIIT workouts. There is a virtually endless combination of modalities, speeds and resistance levels, so you should never get bored.
Ideally you’ll get it done in about 20-25 minutes. If you can go longer than 25 minutes, you’re not working hard enough. Have fun!