I like to do HIIT on the treadmill. Right now I'm doing:
5 minute warm-up of speed walking
1.5 minute sprint
2 minute speed walking to light jogging
Repeat x 6
5 minute cool down of walking
I'm working on increasing my high-intensity intervals and speeds. This is accustomed to each person's limits and levels. You just have to find what works for you. This can also be done on the elliptical, stair master, or bike. It's extremely versatile!
So, why HIIT?
Burn more fat. The high exertion your body goes through fires up its repair cycle. This keeps your body burning calories long after your workout is complete.
Increase stamina. When you push your limits, you'll be able to go longer and harder later on. Get in that anaerobic zone!
Lose weight, keep muscle. This is the most important to me, as I'm trying to build my muscle and cut. When HIIT is mixed with strength training, you maintain the muscles you've worked so hard for and shed body fat.
Revved metabolism. HIIT stimulates production of your HGH (human growth hormone), which gives your caloric burn a swift kick into high gear.
Shorter workouts. Sometimes we just don't have the time for long workouts. HIIT is short and sweet, but extremely challenging and gives you results.
No boredom. You're constantly changing speeds and intensity, which makes this workout anything but boring. Sometimes that long, steady pace can be so mind-numbing!
So, now that you know...why not HIIT?