High-intensity interval training (HIIT)
Also called High-Intensity Intermittent Exercise (HIIE) or sprint interval training, is an enhanced form of interval training, an exercise strategy alternating periods of short intense anaerobic exercise with less-intense recovery periods.
HIIT is a form of cardiovascular exercise. Usual HIIT sessions may vary from 10–35 minutes. These short, intense workouts provide improved athletic capacity and condition, improved glucose metabolism, and improved fat burning.
Studies by Tabata, Tremblay and others have explored the effectiveness of this method compared to traditional endurance training methods. A study by Gibala et al. demonstrated 2.5 hours of sprint interval training produced similar biochemical muscle changes to 10.5 hours of endurance training and similar endurance performance benefits.
According to a study by King, HIIT increases the resting metabolic rate (RMR) for the following 24 hours due to excess post-exercise oxygen consumption, and may improvemaximal oxygen consumption (VO2 max) more effectively than doing only traditional, long aerobic workouts. Tabata's 1997 study concluded that "intermittent exercise defined by the IE1 protocol may tax both the anaerobic and aerobic energy releasing systems almost maximally."
High-intensity interval training has also been shown to improve athletic performance. For already well-trained athletes, improvements in performance become difficult to attain and increases in training volume can potentially yield no improvements. Previous research would suggest that, for athletes who are already trained, improvements in endurance performance can be achieved through high-intensity interval training.
A recent study by Driller showed an 8.2 second improvement in 2000m rowing time following 4 weeks of HIIT in well-trained rowers. This equates to a significant 2% improvement after just 7 interval training sessions. The interval training used by Driller and colleagues involved 8 x 2.5 minute work bouts at 90% of VO2max, with individualized recovery intervals between each work bout.
Long aerobic workouts have been promoted as the best method to reduce fat, as it is popularly believed that fatty acid utilization usually occurs after at least 30 minutes of training. HIIT is somewhat counterintuitive in this regard, but has nonetheless been shown to burn fat more effectively. There may be a number of factors that contribute to this, including an increase in resting metabolic rate. HIIT also significantly lowers insulin resistance and causes skeletal muscle adaptations that result in enhanced skeletal muscle fat oxidation and improved glucose tolerance.
Recently it has been shown that two weeks of HIIT can substantially improve insulin action in young healthy men. Similarly, in young women, HIIT three times per week for 15 weeks compared to the same frequency of steady state exercise(SSE) was associated with significant reductions in total body fat, subcutaneous leg and trunk fat, and insulin resistance. HIIT may therefore represent a viable method for prevention of type-2 diabetes.
( Source: Wikipedia)
What Are the Benefits?
Knowing and understanding these
HEART ♥ RATE ZONES
will ensure that you work at the right level
to achieve your goals, and it will make
your training more accurate.
Training with a monitor ensures that you reach your max heart ♥ rate and when you rest you wait until you hit the correct training zone before you begin your next exercise, regardless of what the people next to you are or aren't doing, creating a more individualized training experience as oppose to doing intervals based on time as a group.
suitable for performing light cardio to improve blood flow and circulation
ideal of warming up and cooling down
base zone used to target fat stores for use as a main source of energy
ideal for developing general fitness
ideal range for utilising fat stores as an energy source
engages more of the cardiovascular and respiratory systems due to the increasing load
The aerobic zone: ideal for developing endurance and improve lactate thresholds
body relies more on stored glycogen and digested carbs for energy, but around half of your energy will still be supplied from fat stores
The anaerobic threshold limit: body is producing massive amounts of lactic acid
only able to maintain this level for a short period of time.
best zone to increase your VO2 max to improve your body's ability to utilise oxygen
relies on predominantly on your ATP-PC system for energy, with some reliance on glycogen
upper limits of your physical capacity
should only ever be reached during HIIT for a short period of time, if at all
Why Do the Numbers Matter?