Bolstered by decades of real-world results, all this research is coming to two clear conclusions:
1) If you aren't doing HIIT, you're missing out
More specifically, you are:
-Missing out on faster times, stronger lifts and better results,
-Wasting unnecessary time training,
-Risking avoidable injury
-Carrying excess body fat and weight.
2) Even if you ARE doing HIIT, you'll want to be careful
By definition, HIIT is an intense stress - on your musculature, bones, connective tissue, energy reserves, mental capacity, and autonomic nervous system. Misuse can quickly lead to inadequate recovery, burnout, loss of training gains, illness and injury.
In other words, it is essential to understand how to deploy HIIT in a balanced, individualized manner.