"If you're still not doing interval training, you're likely wasting an awful lot of time in the gym. This is one of the most important developments in fitness science that I can think of, as you can reap far greater health benefits in less time.
But I've recently also started talking about the potential health benefits of intermittent fasting and working out in a fasted state (i.e. skipping breakfast before hitting the gym).
When you exercise while fasting, it essentially forces your body to shed fat, as your body's fat burning processes are controlled by your sympathetic nervous system (SNS), and your SNS is activated by exercise and lack of food. The combination of fasting and exercising maximizes the impact of cellular factors and catalysts (cyclic AMP and AMP Kinases), which force the breakdown of fat and glycogen for energy.
Evidence is indeed mounting in support of this strategy, and I believe it could be quite beneficial, provided you've already made some fundamental lifestyle changes with regards to diet and exercise.
When combined, high-intensity exercise and intermittent fasting could very well be a winning strategy to bring your fitness to the next level.
Keep in mind that fasting, or exercising in a fasted state, would be unwise if you're still eating a diet full of processed foods, so addressing your diet is absolutely crucial before you venture into any kind of fasting. Also, when undertaking any kind of calorie restriction, such as intermittent fasting or simply skipping breakfast, it's critical to cut the right calories, namely carbohydrates (those from sugars and grains that is, NOT vegetable carbs)."
Dr. Mercola :D
Carb Restriction May Improve Performance in Elite Athletes
A recent study from the Swedish School of Sport and Health Sciences shows that restricting carbohydrates can help burn calories more efficiently and increase muscle oxidative potential even in highly trained athletes.
Ten elite level cyclists performed one hour of interval training at approximately 64 percent of maximal aerobic capacity with either low or normal muscle glycogen levels, achieved by prior exercise or diet intervention. Muscle biopsies were taken before and three hours after exercise. Results showed that exercising in a glyocogen depleted state increased mitochondrial biogenesis. (Mitochondrial biogenesis is the process by which new mitochondria are formed in your cells.)
According to the authors:
"We conclude that exercise with low glycogen levels amplifies the expression of the major genetic marker for mitochondrial biogenesis in highly trained cyclists. The results suggest that low glycogen exercise may be beneficial for improving muscle oxidative capacity."
Part of what makes working out in a fasted state so effective is that your body actually has a preservation mechanism that protects your active muscle from wasting itself. So if you don't have sufficient fuel in your system when you exercise, you're going to break down other tissues but not the active muscle, i.e. the muscle being exercised.
According to fitness expert Ori Hofmekler, author of The Warrior Diet, you can quite literally re-design your physique using a combination of under-eating and exercise.
Interval Training Burns More Calories in Less Time
In related news, research presented at the Integrative Biology of Exercise VI meeting in Colorado on October 10-13 this year, demonstrated that high-intensity interval training burns more calories in less time – a mere 2.5 minutes, divided into five 30-second sprint intervals at maximum exertion, each followed by four minutes of light pedaling to recuperate, can burn as much as 220 calories. All in all, in less than 25 minutes total, you can burn more calories than you would if you were cycling at a moderate pace for half an hour.
According to lead researcher, exercise physiology graduate student Kyle Sevits:
"'You burn a lot of calories in a very short time... Nearly all the calories are burned in those 2.5 minutes; you burn very few during the rest period.' He also points to additional benefits that come from interval training, including increased insulin sensitivity and glucose tolerance, both of which are important for overall good health."
High-intensity interval training, which is part of my total Peak Fitness program, has also been shown to produce greater health benefits overall than conventional aerobic training. Back in April, I reported on a study that found doing just three minutes of high-intensity training per week for four weeks, could lead to significant changes in important health indices, including a 24 percent improvement in insulin sensitivity.
Another important benefit of high-intensity interval training is its ability to naturally increase your body's production of human growth hormone (HGH), also known as "the fitness hormone." HGH is a synergistic, foundational biochemical underpinning that promotes muscle and effectively burns excessive fat. It also plays an important part in promoting overall health and longevity. This is something you cannot get from conventional, aerobic endurance training.
How to Maximize the Health Benefits of Peak Fitness Training
While it's theoretically possible to reap valuable results with as little as three minutes (plus rest periods in between spurts) once a week, it would be more beneficial doing them two or three times a week for a total of four minutes of intense exertion per session, especially if you are not doing strength training. You do not need to do high-intensity exercises more often than that however. In fact, doing it more frequently than two or three times a week can be counterproductive, as your body needs to recover between sessions.
Intensity is KEY for reaping all the benefits interval training can offer. To perform it correctly, you'll want to raise your heart rate to your anaerobic threshold, and to do that, you have to give it your all for those 20 to 30 second intervals. Different studies will use different intervals of exertion and recuperation. For example, in the featured study on elite athletes, bouts of exertion were separated by four-minute rest intervals. They also didn't "max out" during the exertion phase.
I use and recommend the program developed by Phil Campbell, which will trigger HGH production as you go "all out" during the exertion phase. Here's a summary of what a typical interval routine might look like using an elliptical:
- Warm up for three minutes.
- Exercise as hard and fast as you can for 30 seconds. You should be gasping for breath and feel like you couldn't possibly go on another few seconds. It is better to use lower resistance and higher repetitions to increase your heart rate.
- Recover for 90 seconds, still moving, but at slower pace and decreased resistance.
- Repeat the high-intensity exercise and recovery 7 more times
Benefits of High-Intensity Interval Training
Super-efficient HIIT is the ideal workout for a busy schedule—whether you want to squeeze in a workout during your lunch break or to get in shape for a fast-approaching event. Research shows you can achieve more progress in a mere 15 minutes of interval training (done three times a week) than the girl jogging on thetreadmill for an hour. And according to a 2011 study presented at the American College ofSports Medicine Annual Meeting, just 2 weeks of high-intensity intervals improves your aerobic capacity as much as 6 to 8 weeks of endurance training.
2. Burn More Fat
Not only do you burn more calories during HIIT workouts, but the effect of all that intense exertion kicks your body's repair cycle into hyperdrive. That means you burn more fat and calories in the 24 hours after a HIIT workout than you do after, say, a steady-pace run.
3. Healthier Heart
Most people aren't used to pushing into the anaerobic zone (that lovely place where you can't breathe and you feel like your heart is trying to jump out of your chest). But in this case, extreme training produces extreme results. One 2006 study found that after 8 weeks of doing HIIT workouts, subjects could bicycle twice as long as they could before the study, while maintaining the same pace.
4. No Equipment Necessary
Running, biking, jump roping, and rowing all work great for HIIT, but you don't need any equipment to get it done. High knees, fast feet, or anything plyometric like jumping lunges work just as well to get your heart rate up fast. In fact, some equipment like dumbbells can make HIIT less effective because you want the focus to be on pushing your heart to its max, not your biceps.
5. Lose Weight, Not Muscle
Anyone who has been on a diet knows that it's hard to not lose muscle mass along with fat. While steady state cardio seems to encourage muscle loss, studies show that both weight training and HIIT workouts allow dieters to preserve their hard-earned muscles while ensuring most of the weight lost comes from fat stores. Win/win!
6. Increase Metabolism
In addition to increased fat burning and more muscle preserved, HIIT stimulates production of your human growth hormone (HGH) by up to 450 percent during the 24 hours after you finish your workout. This is great news since HGH is not only responsible for increased caloric burn but also slows down the aging process, making you younger both inside and out!
7. Do It Anywhere
You can do it in a boat, you can do it with a goat. You can do it here or there, you can do it anywhere! Dr. Seuss would have loved HIIT. Since it's such a simple concept—go at maximum effort for a short period of time followed by a recovery period and repeat—you can adapt it to whatever time and space constraints you have.
This is not a workout you can do while reading a magazine or chatting with your friend. Because it's so short, you will be working hard the whole time. The trade-off is this format offers seasoned exercisers a new challenge and new exercisers a quick way to see results. You may be in pain, you may be sucking wind, but you definitely won't be bored!