Updated: May 27, 2021
The best part of High-Intensity Interval Training is that is effective and efficient, meaning you don't need too much time daily to be able to see results. Additionally, the anaerobic characteristic of HIIT allows for higher fat burning and weight loss; however, this type of training incorporates burpees, jumping jacks, plyometrics, and many other strenuous movements that exert maximum force on muscles and joints. As a consequence, HIIT comes with certain health risks. According to a study by the University of Alberta, the type of "all-out exercise" in which the person reaches the peak of breathlessness can cause injuries, decrease immunity, affect people’s emotional state and increase acidity in muscle cells causing dizziness, nausea, and reduced muscle power.
In my very biased opinion, I love HIIT. For a long time, I did functional training as the only program that I could adapt to my busy schedule, but I wasn't aware that I'd get injured because the diet was not matching that training style. Lesson learned the hard way, I have to limit my jumps during workout sessions now and regain strength.
As per research, it is healthier to exercise at 6 points of perceived exertion as per the RPE Scale (Rate of Perceived Exertion), which means you should be breathy but not completely out of breath.
Barre, which is a fusion between Yoga, Pilates, and Ballet has saved my life and kept me on track. The truth is that any exercise can be performed at a high-level interval format. Plus, adding the maximum amount of reps during a timed period can be quite effective without the jumps and strenuous movements.