I'm all for efficiency, and there's a theory that's been doing the rounds for years that you can cram an entire cardio workout into a few short minutes. Sound realistic to you? Then there's a really nice rug I'd like to sell you.
Nevertheless, not one to turn down an opportunity to increase efficiency, I looked into it, and the more I looked, the more it seemed that there was some sort of medical/research consensus around the fact that HIIT (Thats High-Intensity Interval Training to you and me) actually works. It came with warnings about how hard it was - the phrase used by researchers was "elevated levels of discomfort", which doesn't sound too bad when you say it quietly. So I did more research, and here's what I found.
No point in exercising blindly and using up lots of energy when you could be doing so much less work with much greater benefits.
One of the constraints I have is that I work for a living and as a consequence I don't have endless hours of free time to plough into fitness. Unfortunately, my lack of free time is not matched by a similarly reduced level of ambition, and so I'm going to have to go looking for efficiency gains (what the cynics call "short cuts") if I'm to reach the level of fitness I'm hoping for.
Everyone will tell you that "recent advances in medical science" have demonstrated that HIIT (or High Intensity Interval Training) is really effective. It takes only a cursory glance at the Wikipedia page to realise that Sebastian Coe was put on a HIIT regimen by his trainer (who was also his father) back in the 1970s, based on the work of German and Swedish scientists.
Nevertheless, more recent work, carried out mostly during the 1990s, have demonstrated that HIIT works much better than one would assume given the time spent training.
In February 2012, the BBC published an article on HIIT, in which Michael Mosley was put through his paces for a total of 12 minutes of very high intensity exercise over 4 weeks. While he turned out to be a "non-responder" (apparently 20% of the population are very slow to benefit from cardiovascular exercise), his insulin sensitivity improved by a staggering 24%.
One of the proponents of the exercise is Professor Izumi Tabata who performed experiments comparing the benefits of a high-intensity workout to a steady-state aerobic workout. The "Tabata Protocol" is a warm-up, followed by 20 seconds of maximum intensity exercise (170% VO2max) and 10 seconds recovery, repeated 8 times for a total of 4 minutes exercise. This regimen, four days per week, associated to another day of ordinary cardio-vascular training had the same effect as 5 days of cardio-vascular training, with obvious gains in time spent running/cycling/rowing.
But how does it work?
One of the annoying things about HIIT is that it is counterintuitive with respect to many of the things we know about cardio training. Normally we have to exercise 30 minutes on a treadmill before fatty acid utilization kicks in.
The researchers had several suggestions as to the source of the benefits :
Conclusion
To quote Stephen H. Boutcher's article "High-Intensity Intermitteent Exercise and Fat Loss" from the Journal of Obesity (November 2010) :
So I'm going to put the Tabata protocol into my training regimen to see what happens. If I can really get an hour's work of cardio done in 4 minutes (to simplify things slightly), then that means I don't have to choose between weight training and cardio, I can have both in my lunch hour.
Nevertheless, not one to turn down an opportunity to increase efficiency, I looked into it, and the more I looked, the more it seemed that there was some sort of medical/research consensus around the fact that HIIT (Thats High-Intensity Interval Training to you and me) actually works. It came with warnings about how hard it was - the phrase used by researchers was "elevated levels of discomfort", which doesn't sound too bad when you say it quietly. So I did more research, and here's what I found.
No point in exercising blindly and using up lots of energy when you could be doing so much less work with much greater benefits.
One of the constraints I have is that I work for a living and as a consequence I don't have endless hours of free time to plough into fitness. Unfortunately, my lack of free time is not matched by a similarly reduced level of ambition, and so I'm going to have to go looking for efficiency gains (what the cynics call "short cuts") if I'm to reach the level of fitness I'm hoping for.
Everyone will tell you that "recent advances in medical science" have demonstrated that HIIT (or High Intensity Interval Training) is really effective. It takes only a cursory glance at the Wikipedia page to realise that Sebastian Coe was put on a HIIT regimen by his trainer (who was also his father) back in the 1970s, based on the work of German and Swedish scientists.
Nevertheless, more recent work, carried out mostly during the 1990s, have demonstrated that HIIT works much better than one would assume given the time spent training.
In February 2012, the BBC published an article on HIIT, in which Michael Mosley was put through his paces for a total of 12 minutes of very high intensity exercise over 4 weeks. While he turned out to be a "non-responder" (apparently 20% of the population are very slow to benefit from cardiovascular exercise), his insulin sensitivity improved by a staggering 24%.
One of the proponents of the exercise is Professor Izumi Tabata who performed experiments comparing the benefits of a high-intensity workout to a steady-state aerobic workout. The "Tabata Protocol" is a warm-up, followed by 20 seconds of maximum intensity exercise (170% VO2max) and 10 seconds recovery, repeated 8 times for a total of 4 minutes exercise. This regimen, four days per week, associated to another day of ordinary cardio-vascular training had the same effect as 5 days of cardio-vascular training, with obvious gains in time spent running/cycling/rowing.
But how does it work?
One of the annoying things about HIIT is that it is counterintuitive with respect to many of the things we know about cardio training. Normally we have to exercise 30 minutes on a treadmill before fatty acid utilization kicks in.
The researchers had several suggestions as to the source of the benefits :
- Tabata believed that his protocol taxed both the aerobic and the anaerobic systems maximally. Traditional cardio work does not make demands of the anaerobic system unless you push yourself with intervals or fartlek-style work.
- It may be possible that HIIT causes an increase in the victim's RMR (Resting Metabolic Rate), which would imply that calories continue to be consumed at a higher rate several hours after the end of the exercise
- Timmonds believes that HIIT uses much more of the total muscle mass of the body (80% instead of 40%)
- Increased consumption of glycogen stored in muscle tissues improves the muscle's capacity for extracting glucose from the bloodstream, preventing it from being stored as fat
- Improved insulin sensitivity (or decreased insulin resistance, if you're borderline diabetic) results in improved glycogen and trigliceride uptake and helps regulate blood-sugar levels.
Conclusion
To quote Stephen H. Boutcher's article "High-Intensity Intermitteent Exercise and Fat Loss" from the Journal of Obesity (November 2010) :
In conclusion, regular HIIE produces significant increases in aerobic and anaerobic fitness and brings about significant skeletal muscle adaptations that are oxidative and glycolytic in nature. HIIE appears to have a dramatic acute and chronic effect on insulin sensitivity. The effects of HIIE on subcutaneous and abdominal fat loss are promising but more studies using overweight individuals need to be carried out. Given that the major reason given for not exercising is time, it is likely that the brevity of HIIE protocols should be appealing to most individuals interested in fat reduction.
So I'm going to put the Tabata protocol into my training regimen to see what happens. If I can really get an hour's work of cardio done in 4 minutes (to simplify things slightly), then that means I don't have to choose between weight training and cardio, I can have both in my lunch hour.
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