Pushing the Limit
Originally featured in Muscle Media, May 2003 With all of life's demands constantly knocking at your door, it's easy to rationalize skipping those long, drawn out cardio sessions- "There just isn't enough time to workout today." Well, get ready to trash that excuse because now you can get the greatest results with a workout that can easily be incorporated into your busy schedule. No, I didn't team up with Jaime Brenkus to produce the new and improved Seven Minute Abs video; however, I am about to introduce you to the most electrifying cardio workout known to man, High Intensity Interval Training (HIIT). HIIT can be defined as the repeated alternating of higher intensity periods of maximal effort with lower intensity periods of active recovery to satisfy a given workout criterion. An example of this would be to sprint for 20 seconds (maximal effort) and then walk for 40 seconds (active recovery); repeat to satisfy the exercise prescription. When working at higher intensities, the overall duration of the exercise session can be (and should be) significantly shortened, which is great news for those wanting get the most per unit time from their workouts. But that's not all, the benefits of HIIT over moderate-intensity, longer duration cardio are many: 1. HIIT causes you to expend more energy (calories)! Although high-intensity aerobics will burn a little less fat than its moderate-intensity counterpart during the exercise session, the total number of calories (and fat) burned as a result of high-intensity exercise is substantially greater than that associated with activity of lower intensity. This is due to an increased excess post-exercise oxygen consumption (EPOC). In other words, the number of calories burned during the hours following a high-intensity exercise bout is greatly increased due to a prolonged increase in oxygen consumption. You burn more calories by just sitting there! With low to moderate intensity cardio, EPOC is minimal, thus metabolism quickly returns to baseline following the exercise session [6,7]. 2. HIIT yields greater fat loss! In one particular study, individuals performed either an endurance training (ET) or HIIT training program for a period of 15-weeks. At the end of the testing period, the HIIT group experienced nine times the fat loss of the endurance training group [2]! This is certainly supported empirically by the many individuals who have experienced accelerated fat loss after adopting HIIT as their form of cardiovascular exercise. 3. HIIT gets you in bad ass shape! High-intensity interval training has proven to increase both one's aerobic and anaerobic capacity; endurance training only increases the former [1,2,3,4]. Moreover, HIIT has been shown to increase one's aerobic capacity even more so than endurance training [4]. One study showed a 14% increase aerobic fitness and a 28% increase in anaerobic capacity in only 14 weeks when following a high-intensity workout regimen [4]. By now, it should be obvious that HIIT is the way to go to make the most of your time, accelerate fat loss, and greatly improve your level of fitness. There is still one problem, however. HIIT is brutally demanding; unless your current fitness level is substantially above average, you will likely fail at completing even a short HIIT exercise session. While this is an obvious problem (if you can't perform the workouts, your chances of reaping the results of such training are zero) it can easily be circumvented. The table below outlines a 12-week, progressive program that I have designed for anyone interested in gradually moving towards HIIT training. At the end of the 12 weeks, you will truly be in what is referred to by my colleague John M. Berardi as "bad ass shape." Week 1, Workout 1: 20 minutes @ 70% of HRmax Week 1, Workout 2: 25 minutes @ 70% of HRmax Week 1, Workout 3: 30 minutes @ 70% of HRmax Week 2, Workout 1: 20 minutes @ 75% of HRmax Week 2, Workout 2: 25 minutes @ 75% of HRmax Week 2, Workout 3: 30 minutes @ 75% of HRmax Week 3, Workout 1: 20 minutes @ 80% of HRmax Week 3, Workout 2: 25 minutes @ 80% of HRmax Week 3, Workout 3: 30 minutes @ 80% of HRmax Week 4, Workout 1: 20 minutes @ 85% of HRmax Week 4, Workout 2: 25 minutes @ 85% of HRmax Week 4, Workout 3: 30 minutes @ 85% of HRmax Week 5, Workout 1: 5 sprint intervals Week 5, Workout 2: 5 sprint intervals Week 5, Workout 3: 6 sprint intervals Week 6, Workout 1: 6 sprint intervals Week 6, Workout 2: 7 sprint intervals Week 6, Workout 3: 7 sprint intervals Week 7, Workout 1: 8 sprint intervals Week 7, Workout 2: 8 sprint intervals Week 7, Workout 3: 9 sprint intervals Week 8, Workout 1: 9 sprint intervals Week 8, Workout 2: 10 sprint intervals Week 8, Workout 3: 10 sprint intervals Week 9, Workout 1: 11 sprint intervals Week 9, Workout 2: 11 sprint intervals Week 9, Workout 3: 12 sprint intervals Week 10, Workout 1: 12 sprint intervals Week 10, Workout 2: 13 sprint intervals Week 10, Workout 3: 13 sprint intervals Week 11, Workout 1: 14 sprint intervals Week 11, Workout 2: 14 sprint intervals Week 11, Workout 3: 15 sprint intervals Week 12, Workout 1: 15 sprint intervals Week 12, Workout 2: 15 sprint intervals Week 12, Workout 3: 15 sprint intervals NOTE: Your age predicted maximum heart rate (APMHR) can be obtained by simply subtracting your age from the number 220. For example, if you are 30 years old, your APMHR is 190 beats per minute (bpm). Therefore, if following the complete program above, your first workout would be 20 minutes in duration and would be performed at The workouts of weeks 1-4 are performed at the conventional percentage of maximum heart rate (HRmax). Within each week, the duration of each workout is increased by 5 minutes while the exercise intensity remains constant. At the beginning of each new week, the duration is reverted back to 20 minutes while the intensity is increased by 5%. By gradually increasing the workload through the manipulation of both the duration and intensity variables, you will effectively prepare yourself for the higher intensity sprint work that is to follow. For the sprinting portion of the program, each interval should be one minute in duration; 20 seconds of maximal effort and 40 seconds of active recovery. Each workout should begin with a light warm-up and stretching and should be concluded with continued walking until your breathing rate has returned to normal. An additional interval is added to every other workout to ensure progressive overload and continual progress. The goal is to perform 15 high intensity intervals in a single workout; there is no need to go any higher than this. Also, it should be noted that you do not have to begin the program with the first workout listed above. If you feel that your current level of fitness is such that you are able to begin with the workouts given in week 4, or week 7, etc, then by all means, do so. However, do not push yourself too quickly; if you are not used to this type of training, it is recommended that you follow the program as outlined. Timing and Pre/Post-workout Nutrition I recommend conducting all cardiovascular activity in the morning to take advantage of the prolonged increase in metabolism. It is OK to have a small meal before your session as doing so improves performance and has a negligible impact on energy substrate utilization both during and after exercise [9,10,11,12]. As far as post workout nutrition is concerned, it is fine to go ahead and supplement with fast digesting proteins and carbohydrates immediately following your HIIT session. While the theory of waiting an hour before consuming a post workout meal/beverage sounded solid, it didn't hold up when research put it to the test. Conversely, research shows that consuming quickly digested nutrients immediately following high intensity cardiovascular exercise actually increases EPOC, reduces muscle protein catabolism, and increases recovery, all while having no adverse effect on lipolysis (fat burning) [8]. For more information, see my article Active Nutrition. Mixing Things Up Once you have completed the program, you can avoid boredom and stagnation by making some adjustments to your HIIT sessions. An easy and effective way to do this is to manipulate the work to rest ratio of each session. In the above program, the work to rest ratio was set at 1:2 (20 seconds sprint, 40 seconds walk). Other work to rest ratios that have proven to be successful are 1:1/2, 1:1, and 1:3 [1,3,4,5]. Below are some example programs using each: Work to Rest Ratio- 1:1/2 Sprint 20 seconds/Walk 10 seconds, repeat 8-10 times Work to Rest Ratio- 1:1 Sprint 20 seconds/Walk 20 seconds, repeat 10-12 times Work to Rest Ratio- 1:3 Sprint 20 seconds/Walk 60 seconds, repeat 12-15 times The only time I would change the mode of exercise (from sprinting to another mode such as cycling, rowing, stair stepping, etc) is if the weather is not conducive to sprinting outdoors. Sprinting is by far the most convenient, most effective form of HIIT. That's All Folks Time is of the essence, and so are the results that you obtain from the work you put in. If you want to maximize your results in the shortest amount of time, then HIIT is the mode of choice. By working your way up to this type of intense training, you'll feel great, look great, and free up more than enough time to send me an email screaming about how much progress you've made.
References 1. Rodas G, et al. A short training programme for the rapid improvement of both aerobic and anaerobic metabolism. Eur J Appl Physiol. 2000 Aug;82(5-6):480-6. 2. Tremblay A, et al. Impact on exercise intensity on body fatness and skeletal muscle metabolism. Metabolism 1994 Jul;43(7):814-8. 3. Tabata I, et al. Metabolic profile of high intensity intermittent exercises. Med Sci Sports Exerc 1997 Mar;29(3):390-5. 4. Tabata I, et al. Effects of moderate-intensity endurance and high-intensity intermittent training on anaerobic capacity and VO2max. Med Sci Sports Exerc 1996 Oct;28(10):1327-30. 5. Gullstrand L. Physiological responses to short-duration high-intensity intermittent rowing. Can J Appl Physiol 1996 Jun;21(3):197-208. 6. Bahr R, et al. Effect of Intensity on Excess Post exercise O2 Consumption. Metabolism 40.8 (1991) : 836-841. 7. Smith J, et al. The Effects of Intensity of Exercise and Excess Post-Exercise Oxygen Consumption and Energy Expenditure in Moderately Trained Men and Women. European Journal of Applied Physiology 67 (1993) : 420-425. 8. Lee YS, et al. The effects of various intensities and durations of exercise with and without glucose in milk ingestion on postexercise oxygen consumption. J Sports Med Phys Fitness. 1999 Dec;39(4):341-7. 9. Diboll DC, et al. Cardiovascular and metabolic responses during 30 minutes of treadmill exercise shortly after consuming a small, high-carbohydrate meal. Int J Sports Med. 1999 Aug;20(6):384-9. 10. Bahr R, et al. Effect of feeding and fasting on excess postexercise oxygen consumption. Appl Physiol. 1991 Dec;71(6):2088-93. 11. Bergman BC, et al. Respiratory gas-exchange ratios during graded exercise in fed and fasted trained and untrained men. J Appl Physiol. 1999 Feb;86(2):479-87. 12. Schabort EJ, et al. The effect of a preexercise meal on time to fatigue during prolonged cycling exercise. Med Sci Sports Exerc. 1999 Mar;31(3):464-71. |
