Cardio Exercise At HIIT Or Target Heart Rate?
There are two popular ways of performing cardio exercise to lose weight: training at your target heart rate zone, and using high-intensity interval training (HIIT). Training at your target heart rate zone involves maintaining your heart rate at a fixed number to put your body in the most optimal fat-burning mode. HIIT takes a different approach, switching between different types of training quickly to elevate your metabolism. But which is most effective for losing weight?
Finding your heart rate
Your heart rate is your heartbeats per minute, also known as your pulse. Finding your heart rate at any given time is very simple: place your index and middle fingers in the hollow to the side of your throat, next to your windpipe. You can also use your wrist, but I find it easier to use my neck. Count how many pulses you have for 15 seconds, then multiply that number by 4. This will give you your heart rate. At rest, your heart rate should be around 60 - 80.
Target heart rate
First, we must learn two important numbers, your target heart rate and maximum heart rate.
- Maximum heart rate: 220 - your age
- Target heart rate: 65% of maximum heart rate
If you are 20 years old, your maximum heart rate is 200, and your target heart rate is 130. So at 130 heartbeats per minute, your body is in the optimal zone for burning fat.
By “optimal,” I mean burning the most amount of calories from fat. If your heart rate (HR) goes above your target heart rate, your body will be less effective at using calories from fat. Here is a rough breakdown:
- 65% HR (or less): 85% from fat
- 75% HR: 50% from fat
- 85% HR: 15% from fat
Note that although higher heart rate means more intensive workouts, since the percentage of calories burned from fat is lower, the overall calories lost may drop as well. A more intensive workout DOES NOT necessarily burn more calories.
Training at the target heart rate zone seems to be a solid way of losing fat. But is it the most optimal way?
HIIT: High-Intensity Interval Training
Whereas target heart rate training is done at a constant speed, high-intensity interval training is done with short bursts of sprinting and walking. My current HIIT cardio schedule looks like this:
- 1 minute: Walk @ 3MPH
- 10 minutes: Jog @ 5MPH
- 10 minutes: HIIT - alternate between 9.5MPH and 2MPH
- 10 minutes: Cooldown, jog @ 5 MPH
- 1 minute: Walk @ 2MPH
HIIT cardio breakdown
- I walk for 1 minute in the beginning to warm up for the jog. Always warm up before you do any exercise.
- I then jog for 10 minutes to warm up for the sprints in the next stage.
- For the next 10 minutes, I do five 2-minute sessions. In each session, I sprint at 9.5 MPH for one minute, then walk at 2 MPH for one minute.
- When I am done with HIIT, I cool down by jogging for 10 minutes, then walking for one minute.
Why HIIT is different
HIIT, instead of training in the target heart rate zone, forces you to alternate between two extremes: walking and sprinting.
While training at your target heart rate does make your body enter its mode of burning fat the fastest, the body resumes to its resting heart rate relatively shortly after the exercise. But with HIIT, the body’s heart rate remains elevated for a much longer time past the workout. Thus, HIIT burns more calories throughout the day and is more effective in burning calories from fat.
Warning
If you are starting HIIT for the first time, sprint at a speed you can handle. When I first started, I sprinted at 6 MPH, and was gradually able to build to my current speed. Do not make yourself excessively uncomfortable while doing HIIT. It only takes one time for you to go overboard and injure yourself.