Weight-loss with High Intensity Interval Training or HIIT
Weight loss for the New Year and getting the most of your cardio workout.
Being that the New Year is upon us, and understanding that many of you might have New Year’s resolutions which involve weight loss, I thought it would be helpful to shed some light on the matter. There exist many misconceptions in regards to nutrition, health, exercise and weight loss, this article specifically deals with the misunderstandings of cardio-respiratory or simply cardio training.
Let us start with a quick review of some of our cells energy pathways. Our cells need energy to perform work, the form of energy our cells utilize is Adensoine Triphosphate or ATP. Mammalian muscle cells utilize three basic pathways for ATP or energy replenishment.
1. The Phosphagen System
3. The Oxidative System
The Phosphagen system and the first part of Glycolysis do not require the use of oxygen to replenish ATP and as such are referred to as being Anaerobic. The last portion of Glycolysis and the Oxidative system do require oxygen to replenish ATP and are termed Aerobic. For ease of discussion, if you are working out at an intensity that you could easily carryout a conversation “sweating to the oldies” you are probably utilizing an aerobic pathway. Consequently, if you are breathing heavily as if you just got done running from a lion, you’re utilizing an anaerobic pathway.
Long drawn-out low intensity workouts are not beneficial. Low intensity workouts tend to be more aerobically based exercises and aerobics are inferior in terms of total calories burned and fat loss in the long term. Aerobic exercise is important for athletes whom want to participate in marathons, triathlons, excreta. Even if you are a distance athlete, you’re not exercising most efficiently if all you do is aerobic training. Training aerobically for long periods of time will increase the likely hood of an “overuse” or “repetitive” injury. Training aerobically long term will also increase your likely hood of having a poor hormonal environment that is more apt at maintaining or even adding weight, or at the very least not losing weight as fast as possible.
So what’s the answer, in designing a workout program for our patients I seldom recommend cardio-training to last longer than 20 minutes, in addition to the proper warm up and cool down. When putting together a cardio program we need to have a focus on anaerobic exercise. Think for a second about the difference in bodies between a distance runner and a sprinter. Many of you have gone to the gym and seem someone plugging away at a low speed for hours on a treadmill, now compare that physique to someone who sprints on a regular basis. When you use larger muscles at a higher force production you will burn more total calories. In addition this type of training if properly designed will create a hormonal environment that is more conducive to fat loss, while maintaining the muscle you currently possess. Maintaining muscle is important because the more muscle you have the more fat you will potentially burn.
So if the question is “how can we get the most out of our cardio training”? High Intensity Interval Training or HIIT is the answer. HIIT is a cardio program structured to give you a “resting session” followed by a “working session” the exercise session goes back and forth between working and resting. “Properly spaced work to rest intervals allow more work to be accomplished at a higher exercise intensities with the same or less fatigue than during continuous training”. (Baechle & Earle, 2008) In general the program alternates between work and rest with a total of about 8 working sessions. The working portions can last for as little as 20 seconds to as long as 40 seconds depending on intensity. The resting portions can last from 1 to 1 ½ minutes depending on intensity.
To be even more specific and to lessen the chances of either over or under training a heart rate monitor can be used. The book Advances of Functional Training (Boyle, 2010), the book outlines such a protocol using the Karvonen Formula or the “Heart rate reserve method” the formula is:
- Maximum heart rate minus resting heart rate times percent, plus resting heart rate (RHR) equals theoretical heart rate (THR)
Example 200-60 x 0.8 + 60 = 172
Thus after the working portion has been performed, the recovery portion is determined to be reached when your heart rate returns to the resting heart rate or RHR.
Some of the benefits of High intensity interval training include:
- Less total workout time
- Less “wear and tear” on the joints due to less total workout time
- Better muscle buffering capacity
- More total work = more calories burned
- More Growth Hormone and testosterone release
- Faster improvement in endurance, even in distance events
Remember that your body does become adapted to exercise, in order to consistently make progress changes should be made routinely. In regards to your choice of HIIT you may use the discussed parameters for running, sprinting, bicycling, rowing, or any other form of cardio you enjoy…just make it fun and keep the intensity up.
Obviously, I’m not advocating any one exercise for all patients or athletes. Everyone is different with different needs, goals, genetics etc. This article is not intended to diagnose or treat any disease and if you are new to exercise having a per-participation physical is advised in addition to a movement screening. If you are already injured then being properly examined, diagnosed and treated prior to exercise is essential. As always feel free to contact our office with any questions.
Baechle, T. R., & Earle, R. W. (2008). Essentials of Strength Training and Conditioning. Champaign IL: Human Kinetics.
Boyle, M. (2010). Advances in Functional Training. Santa Cruz CA : On Target Publications.