HIIT may not be appropriate for individuals experiencing hypertension for many reasons including, if you’re a newcomer to fitness, you have high-uncontrolled BP, have just lost a loved one, etc, the doctor warns and explains the body needs time to recover from these intense oxygen deficits caused by brief out of breath intervals. “HIIT exercise programs that entail out-of-breath intervals create rapid increases and decreases in BP, ultimately stressing or straining the cardiovascular system. The more strenuous cardio sessions ,intense long-distance running, extreme endurance workouts like cross fit, sprinting, etc. should therefore be implemented carefully,” he explains.