High Intensity Interval Training

The basic idea behind High Intensity Interval Training is to go fast and then slow. The ideal HIIT cardio program is designed to stimulate your metabolism just enough so that you can burn fat all day and all night over the next 48 hours, yet it is not so long that it will cause muscle-wasting catabolism.

This translates to a few minutes for warmup, then short periods of maximum-effort sprinting (or other activity) alternated with short periods of rest, and then concluded with a cool down period.

Interval training requires longer recovery time, so should only be performed 2-3 times per week. To continually challenge yourself you should increase effort on each session.

Here's a tip: Most people use time-based or distance-based measurements for their HIIT session, but consider using heart-rate measurements instead. You will need to determine your maximum heart rate and then try to get as close to this as possible during the sprinting periods.

Example of Time-Based HIIT Routine:
Walk fast or jog for five minutes to warm up.

Sprint for 20 seconds at maximal effort.
Rest for 15 seconds.
Sprint for 20 seconds at maximal effort.
Rest for 15 seconds.
[Repeat the above three more times for a grand total of eight sprints.]

Cool Down for five minutes.

Substituting my heart rate method for the time-based one above is a little more complicated. Your heart rate will continue to rise during the cool down period so you will probably want to reach near 90% of your max during the sprint, then rest until the heart rate slows down to approximately 70% of your max, depending on your recovery ability. Repeat this seven more times for a total of eight sprints.

High Intensity Interval Training

• Improves aerobic capacity and helps to burn fat.
  
• Suppresses the appetite.
  
• Improves sports performance and sprinting capabilities.
  
• Results in greater post-exercise energy usage and fat utilization.
  
• Causes Human Growth Hormone to be released into the bloodstream.
  
• Builds Muscle.
  
• Increases your lactic acid threshold.
  
• Takes only a few minutes to perform.
  

Summary: HIIT stimulates the metabolism for many hours after being performed. The body must burn more calories to recover from the HIIT session, so the net calories burned per HIIT session is greater than the typical Long Slow Cardio session. HIIT does not take very long and is more challenging and rewarding than slogging away on a treadmill for an hour a day.

Most of the principles of HIIT were derived from the work of Dr. Tabata from the National Institute of Health & Nutrition in Tokyo, Japan. Dr. Tabata embarked on a mission to find the ideal aerobics protocol. Such a plan, he decided should have the following components:

• Must Be Intense: He knew that high intensity exercise means more fat is burned during the rest of the day after the session. The metabolism is stimulated and the total calories burned will be 50% over Long Slow Cardio sessions.
  
• Must Promote Fitness: Dr. Tabata wanted exercise that would promote aerobic and anaerobic fitness. He knew that the more fit you are, the more likely you are to use fat as fuel for a given activity.
  
• Must Be Brief: Dr. Tabata wanted to preserve muscle, which is important for maintaining a healthy metabolism.
  

His ideas were mainly influenced by speed skaters, who have excellent muscular development and single-digit bodyfat percentages.

Dr. Tabata performed a study on his new workout method. His high intensity subjects had a 14% increase in VO2 peak and a 28% increase in anaerobic capacity at the end of the study. His moderate-intensity group had a 10% increase in VO2 and no increase in anaerobic capacity at the end of the study.