The short story: getting more for less…with a little more effort.
Scientists have known for years the benefits of interval training. The goal of cardiovascular (CV) training is to improve endurance and stamina. CV training also burns calories and fat, a primary reason for most of us to exercise. Interval training however, is the process of pushing one’s body to it’s maximum for short bouts of work, recovering, then repeating. High intensity interval training has been proven to dramatically increase and improve cardiovascular output.
HIIT workload is about 90-95% of our maximum HR (heart rate) and VO2 max. VO2 max, also known as maximal oxygen consumption or maximal aerobic capacity, is the capability of the body to consume oxygen for producing energy. VO2 max has long been considered a gold standard for predicting our ability to perform during exercise.
Most of us spend 20-60 minutes running, cycling, stair-mastering, or another form of activity, to stay in “shape”. This type of workout is an endurance based, steady state workout. HIIT improves VO2 max, (our “shape”) as much as, or even more than endurance training.
The benefit of HIIT is the results match and often surpasses endurance training, with shorter workouts.
HIIT workouts can be done with any modality of aerobic training. The “work” portion can be anywhere from 5 seconds to 8 minutes; the “rest/recovery” portion can be a low active recovery, or higher of 70% of HRmax. The work to rest ratio can be 1:1, 2:1 or 1:2. Your interval work can be as short as 10 minutes, up to 25-30 minutes. Warming up and cooling down for 6-10 minutes is also important.
A 1:1 example of a HIIT session could be a 2-minute bout of work, followed by a 2-minute rest, repeating the series 4-7 times.
Because the workout is intense, placing high demands on the body, the recommendation is to compliment HIIT with your regular workouts, doing no more than 3 HIIT workouts per week. This helps to avoid injuries.
Anyone in good fitness condition can do HIIT training. HIIT is not recommended for beginners. Those with cardiac respiratory health issues should get permission from their doctors before starting this exercise regimen.
Unsure whether this is right for you? Check with your doctor before beginning this high intensity program.
Zuhl, Micah, MS & Kravitz, Len, PhD. IDEA Fitness Journal. February 2012