HITT stands for High-intensity interval training.
The idea behind it is to maximize your aerobic capabilities while maintiaining muscles and burning fat.
It can be done for anywhere between 15-20 minutes, but after 20 minutes, you risk losing muscles.
You do it by having a nice warm up, then several short maximum intensity effort, with minimum rest between, and then a cool down.
For example,
On a treadmill,
5 minutes warm up by walking fast
2 minutes jog
1 minute sprint
2 minutes run
1 minute sprint
2 minutes jog
1 minute fast walk
2 minutes sprint
1 minute jog
2 minutes run
1 minute fast walk
5 minutes cool down by walking
The idea behind it is to reach your maximum heart rate. At the end, you're supposed to feel exhausted like you cannot do it for another minute.
