Time is the enemy of fitness. When people see official recommendations that they need to do 60 to 90 minutes of exercise per day to lose any fat, this turns a lot of people off to the idea of even trying to get into shape. Who has seven to 10 extra hours in a week to go jogging or whatever?
Luckily, there is good news: You don’t actually need to spend that much time exercising in order to get great results. There are at least 15 years of research showing that you can get better results in less time with high-intensity interval training and strength training if you do it right.
When I talk about results, I’m talking about both cardiovascular fitness and fat loss. Beyond better results, interval training and strength training will save you time, put less wear and tear on your joints and are less boring than plugging away for an hour on a machine at the gym.
There are at least three reasons why high-intensity interval training and strength training work better and take less time. The first is that these kinds of exercise don’t make people as hungry as long, slow “cardio.” The problem with long, slow exercise like jogging is that it tends to make people disproportionately hungry. That is, if you expend 400 calories jogging, your appetite usually goes up more than that. However, with the shorter, high-intensity workout, it does not seem to have the same appetite-stimulating effect – actually, it seems to have a slight appetite-suppressing effect.
The second reason is a post-workout metabolic boost. Research has shown that exercise like resistance and interval training elevates your resting metabolism and shifts your body to want to burn its own fat for 24 to 36 hours (or until your next high-carb meal). Exercise once and reap benefits all day long.
The third reason is that resistance and interval training boost growth hormone naturally. Two years ago, a study on this came out, and one of the authors, Jeff Ross, said this: “The only way to get better results in body-fat loss is surgery.”
Co-author Phil Campbell said, “Our study on middle-aged working adults shows that targeting growth hormone with (a high-intensity interval training workout) gets twice the results of injecting growth hormone in body-fat loss.”
One of the most common mistakes people make when starting out with interval training is that they try to eliminate the necessary rest or recovery breaks. Most people are so used to getting on a treadmill and plodding away for an hour that the idea of exercising for only 10 to 20 minutes sounds insane, especially when they will be in recovery most of the time. The recovery period isn’t there to be nice. It’s there so you can work as hard as possible – and it’s what makes it effective. By definition, you just can’t keep up your top speed for more than a few seconds. Longer means slower, which is counterproductive.
The next most common mistake people make is going in the opposite direction – taking it too easy. People try to use something like “intervals” of fast walking and slow walking. Unless you are extremely deconditioned, then this just won’t work because you can’t generate enough intensity with walking. Even if this really is enough for you in week one, it won’t be very soon, so remember to step it up. Your “fast” portion interval training needs to be hard enough that you need to stop, and walking rarely fits the bill for the “work” part, but it’s great for the recovery part. Running (even for very short periods of time) is a nice complement to walking. Many people who think they “can’t run” because it hurts their knees actually find that this allows them to run pain-free because they get these built-in breaks and their running technique doesn’t breakdown from running for too long.
The last mistake we’ll cover is people doing “intervals” for too long. Just because something feels “hard” or is awful does not mean it is effective. Pain and sweat are not results, results are results. In general, you’re only going to get 15 to 25 minutes of quality interval training work in a workout. If you’re doing 45 or 60 minutes of interval training, it’s just because your intensity is too low. If you want maximum fat-loss results, focus on quality, not quantity.