HIIT done right is a great form of exercise that will make a perfect addition to your workout program. HIIT done wrong could lead to injuries, burn out, and loss of motivation to continue.
Realize that your body can only handle so much intense exercise per week. If you attempt to do HIIT and full-body weight lifting sessions 5 or 6 days a week, it’s only a matter of time before your system crashes. Remember that even though you may be working different muscles on successive workouts, your central nervous system will still be working hard, generating the strength and power needed to get these sessions done. It needs rest time, too. Even the most fit of individuals should cap it off at four very intense workouts total a week if you’re advanced, or three if you’re at the intermediate level.