Sometimes it’s hard to wade thru headlines and know that what you are doing is what you need to be doing. Several years ago, information about a study related to low to moderate activity burning the most fat was widely circulated. This led to a lot of confusion about which type of cardio activity is “best” for weight loss. While low to moderate exertion does burn a higher percentage of fat VS glycogen (energy stored in the muscles), the fact remains that it is total caloric expenditure that is important – especially when weight loss is the goal.
Keeping in mind the simple equation of calories in VS calories out, when one expends more calories than they take in, the result will be weight loss, regardless of the activity training mode – or the source of the energy.
Despite the wide misunderstanding of this information, intensity or interval training became the basis of many formats that grew in popularity during the 90’s.
Intensity and Interval Formats
The word “intensity” is used in various modes of exercise, but primarily it is applied to cardio and strength. In strength training, it is often referred to as “high intensity training” (HIT) and applied by serious weightlifters who are training to increase muscle mass, power and size.
In cardio-respiratory activities, intensity training is often referred to as “Interval” training. Olympic track and swim coaches have used interval training for many years to improve their athletes’ overall fitness level and shave seconds off their competitive race times.
The cardio respiratory system is not unlike any other muscle that you work with strength training. The idea is to ask it to do just a little bit more than it is accustomed to doing – to impose a new demand. When you ask your biceps to repeatedly lift a heavier weight than they are used to, they will fatigue, and in the recovery days to follow, your body will repair and build the muscle needed to lift the same weight. This process is known as adaptation.
With Interval training, the goal is to intersperse smaller more manageable bouts of all out effort with periods of low to moderate recovery.
When training at maximum effort, the body can only maintain all-out effort for a short period of time. When reaching Max VO2 threshold and going beyond into anaerobic training, the body taps glycogen stored in the muscles for fuel. The combustion of this fuel leads to a build up of lactate in the muscles. Because the muscles are working hard without oxygen, resulting in subsequent lactate increase and fatigue, the body will begin to slow down to a lower level of exertion and decrease the level of intensity back into an aerobic training mode.
With an understanding that the body will adapt to increased demands, pushing to the anaerobic threshold and beyond results in improvements in MaxVO2, lactate tolerance, and overall fitness level.
The principles of interval training can be applied to any mode of cardio respiratory training to improve your overall level of fitness.
But that’s not even the best of it! Research on interval training revealed that this type of training also burns more calories than steady state training – not just in the workout itself – but also after the workout. The smaller bouts of intensity allow you to workout longer for a greater volume of work which = a greater total caloric consumption. And after all-out intensity training, the stored glycogen is depleted, leaving only fat to burn post-workout. This total-burn and after-burn is why intensity training has greatly increased in popularity.
But because of the high demands placed on the body for this type of workout, it is recommended that you allow your body to fully recover to reap the full benefits. Interval training should be done generally twice a week, with other workouts in between that focus on steady state or endurance training.