Izumi Tabata, PhD, was ahead of his time. In the October 1996 issue of Medicine & Science in Sports & Exercise, Tabata showed that a certain high-intensity interval training (HIIT) protocol had better aerobic and anaerobic improvements than long-duration endurance exercise (1). Over the past decade, HIIT has become popular for endurance and strength athletes alike, and numerous scientific studies have demonstrated that various HIIT protocols contribute to subcutaneous and abdominal fat loss, increased VO2 max, increased anaerobic capacity, and improved insulin sensitivity. But the venerable Dr. Tabata didn't come up with just any HIIT workout, and it certainly wasn't a "1 minute of work, 4 minutes of recovery" that is prescribed to beginners. His particular brand of pain and suffering consisted of eight intervals of 20 seconds of all-out effort and a mere 10 seconds of recovery. That is a serious tempest of ass-kicking in a four-minute tea cup. Doctor Tabata showed that HIIT- specifically the program that bears his name -induces adaptations that are similar to those of long-duration exercise. Recent research has shown that HIIT is better at reducing both subcutaneous and visceral fat than other types of exercise. Compared with long-duration endurance exercise, HIIT training results in similar GLUT4 content and maximum glucose transport activity (2), similar fatty acid oxidation enzyme activity in skeletal muscle (3), and similar levels of PGC-1alpha protein (4). In addition, HIIT protocols have been shown to increase aerobic and anaerobic fitness, lowers insulin resistance, and improve fat oxidation and glucose tolerance in skeletal muscle (5). The moral of the story is that HIIT produces effects similar to those found in long-duration endurance exercise, all of which are highly desirable for any training program. In addition to aerobic and anaerobic benefits, HIIT protocols augment fat loss. Anecdotally, athletes that undergo a HIIT program notice decreased body fat while retaining (or increasing) muscle strength. Studies involving HIIT protocols show significant decrease in both subcutaneous and visceral fat and waist circumference while still maintaining muscle mass (5, 6). Why does this happen? While physiologists are not certain, possible explanations include increased fat oxidation during and after exercise (ATP resynthesis mainly from intramuscular triacylglycerol stores and greater fatty acid transport, and increased capacity for fatty acid oxidation in both skeletal muscle and whole body) as well as decreased appetite post-exercise. In less than four minutes, the Tabata Protocol maxes out the aerobic and anaerobic systems.Tabata's initial 1996 study (1) compared moderate intensity endurance training (70% VO2 max for 60 minutes, 5 days per week) versus HIIT training (sets of 20 seconds at 170% VO2 max, 10 seconds recovery, 5 days a week) on a cycle ergometer for six weeks. Tabata found that in the endurance-training group, VO2 max increased by 10%, but anaerobic capacity did not change. However, in the high-intensity group, VO2 max increased by 15% and anaerobic capacity increased by 28%. This protocol was tested against other types of HIIT and was found to be the best at maximally stimulating both the aerobic and anaerobic systems (7). How it works: The effect of the Tabata Protocol depends on going hard for 20 seconds and only taking 10 seconds recovery. During the hard, 20-second effort, you maximally recruit muscles. The 10-second recovery does not provide enough time to regenerate your ATP-creatine phosphate system and pay back your oxygen debt, so you begin the next 20-second bout in a deprived state. With each additional 20-second effort, you increase oxygen uptake and reach maximum anaerobic capacity near the end of the protocol. Benefits for strength athletes: The obvious benefits to endurance athletes include increased VO2 max, anaerobic capacity, and increased fat oxidation. Strength athletes also benefit from these results. HIIT produces fatigue similar to resistance training: low phosphocreatine concentrations, increased intramuscular acidosis, and low concentration of intramuscular glycogen (8) on top of increased aerobic and anaerobic fitness. Unlike steady-state endurance training, HIIT is not muscle-wasting. It is believed that muscles can adapt in either an "endurance' manner (i.e. increased mitochondria) or in an "strength' manner (i.e. hyprotrophy). Typical endurance training stimulates the pathways that induce "endurance' adaptations and block pathways that induce hypertrophy. The converse is true for strength training. HIIT is unique in that it induces many benefits of endurance training without increases in PCG-1a expression (mitochondrial biogenesis), without inhibition of protein synthesis and skeletal muscle growth signaling (9), making it a great way to gain endurance adaptations without fear of turning off your strength pathways. Don't be scared. HIIT is not muscle-wasting: It's believed that muscles can adapt in either an "endurance' manner (i.e. increased mitochondria) or in a "strength' manner (i.e. hyprotrophy). Typical endurance training stimulates the pathways that induce endurance adaptations and block pathways that induce hypertrophy. The converse is true for strength training. HIIT is unique in that it induces many benefits of endurance training, such as increases in PCG-1a expression (mitochondrial biogenesis), without inhibition of protein synthesis and skeletal muscle growth signaling (9), making it a great way to gain endurance adaptations without fear of turning off your "strength' pathways. How to do it: I typically have my clients perform the Tabata protocol on a stationary bike, but they can be done with almost anything, such as a treadmill, elliptical, jump rope, push-ups, pull-ups, squats, or even hitting a heavy bag. Warm-Up: 10-15 minutes, including of a couple of short, max efforts of 5 seconds. Main Set: 8x20 seconds max effort, with 10 seconds recovery between work intervals. Cool down: 5-10 minute easy spinning. The good news is, you'll be done in less than 30 minutes. The bad news is, if you're not gasping for air and seeing stars by the end of the workout, you didn't push yourself hard enough. Warning: One disadvantage of the Tabata Protocol is that it is very physically and demanding, and takes a great deal of motivation to complete. Some folks may not be able to handle the stress of the workout and may never want to do it again. I dread the workout and almost cannot stay on the bike near the end of the Tabata Protocol, but I continue to do it because I love the benefits. About the Author: Joe Company competed as a professional triathlete from 2003-2007 and owns Endurance Company, providing training and guidance for endurance athletes. Joe has a master's degree in Exercise Physiology and is currently completing his PhD. in Biomedical Science where he is investigating the effect of exercise and inactivity on adipose tissue health.
- Tabata I, Nishimura K, Kouzaki M, Hirai Y, Ogita F, Miyachi M, Yamamoto K. Effects of moderate-intensity endurance and high-intensity intermittent training on anaerobic capacity and VO2 max. Med Sci Sports Exerc 28(10): 1327-1330, 1996.
- Terada S, Yokozeki T, Kawanaka K, Ogawa K, Higuchi M, Ezaki O, Tabata I. Effects of high-intensity swimming training on GLUT4 and glucose transport activity in rat skeletal muscle. J Appl Physiol. 90_(6): 2019-2024, 2001
- Terada S, Tabata I, Higuchi M. Effect of high-intensity intermittent swimming trainig on fatty acid oxidation enzyme activityin rat skeletal muscle. Jpn j Physiol. 54(1): 47-52,2004.
- Terada S, Kawanaka K, Goto M, Shimokawa T, Tabata I. Effects of high-intensity intermittent swimmingon PGC-1 alpha protein expression in rat skeletal muscle. Acta Physiol Scand. 184(1):59-65, 2005.
- Boutcher SH. High-intensity intermittent exercise and fat loss. J Obesity. 2011.
- Trapp EG, Chisholm DJ, Freund J, Boutcher SH. The effects of high-intensity intermittent exercise training on fat loss and fasting insulin levels of young women. Int J Obes (Lond). 32(4): 684-691, 2008.
- Tabata I, Irisawa K, Kouzaki M, Nishimura K, Ogita F, Miyachi M. Metabolic profile of high intensity intermittent exercises. Med Sci Sports Exerc. 29(3): 390-395, 1997.
- Lambert CP and Flynn MG. Fatigue during high-intensity intermittent exercise: application to bodybuilding. Sports Med. 32(8): 511-522, 2002.
- Gibala MJ, McGee SL, Garnham AP, Howlett KF, Snow RJ, and Hargreaves M. Brief intense interval exercise activates AMPk and p38 MAPK signaling and increases the expression of PGC-1a in human skeletal muscle. J Appl Physiol. 106:929-934, 2009.