High intensity interval training (HIIT) is not a new exercise fad, nor a aimless approach to eliminate aerobic training's inevitable redundancy for the general fitness population. It is a research-backed, fundamental pillar that all ages and abilities can utilize. The use of HIIT has ranged from Olympic athletes, to cardiac rehab patients. The recent surge of HIIT into the general fitness population is here to stay.
What is HIIT?
HIIT is a aerobic program design that combines periods of near-maximal (90% VO2 Max) effort with periods of active (40-60% VO2 Max) recovery. The work rest ratio can be manipulated depending on the individuals fitness level. Work to rest ratios ranging from 1:1 to 1:4 can be used, and still provide fitness benefits. An average HIIT session lasts 30 minutes, making it ideal for quick training sessions.
HIIT relies on maximizing the training effect. In layman's terms, "the biggest bang for your buck". The repeated periods of near maximal effort are accomplished because of the appropriate recovery periods. Lasting a continuous 15 minutes at 90% of an individuals VO2 Max is impossible. However, with HIIT training, the same amount of work can be accomplished when paired with recovery periods.
Why is HIIT important?
Research suggested that HIIT may provide greater improvements in cardiovascular and endothelial function than traditional aerobic training. The three most sought-after improvements found in research via HIIT training are, 1) an improved VO2 Max (the bodies ability to consume and use oxygen), 2) increased fat oxidation ("burning fat") and, 3) an elevated EPOC (excess post-exercise oxygen consumption) which just means that caloric expenditure is elevated even after the HIIT session was completed.
Traditional moderate intensity, prolonged aerobic exercise does all this as well, but just not as effectively. I highly recommend adding HIIT training to everyone who is looking to improve body composition, prevent over-training, or just needing to make better use of their time.
HIIT should be performed twice a week, with varied work to rest ratios if possible. Traditional aerobic exercise of longer, moderate intensity exercise should still be performed. It is the combination of both methods that yields the best results.
Below is a sample HIIT routine taken from Brad Schoenfeld and Jay Dawes in their article titlted, High Intensity Interval Training: Applications for General Fitness Training. (Note, RPE is used instead of percentage of VO2 max. RPE stands for the rate of perceived exertion, also known as, "how hard you think you are working".)
Anton Snyder, CSCS, NSCA-CPT
Human Performance Graduate Student at UW-La Crosse
Personal Trainer at Snap Fitness