The Intensity Paradox

When something becomes effortless, raise the level of intensity, to the point where you can get there without too much resistance, but it’s still somewhat challenging. To put it more concisely, bend but don’t break.

Any exercise can be a form of HIIT, if it follows a specific regimen where you vary your speeds and intensity when doing it.
Example:

• Jogging lightly for three minutes.
• Pushing yourself harder for a minute (run or sprin...

• Wait at least two weeks before starting to increase — that’s the minimum your body needs to adjust. 
• Once it begins to feel way too easy, you can start increasing the length of your workouts, to 30 and then 40 minutes, and eventually up to an hour.
• Once you do t...