For those days when you’re REALLY strapped for time, do you look for ways to get the most done in the least amount of time. Most of us do. You might think there’s no shortcut for getting into shape – but think again. For the past few years, high-intensity interval training has been taking the fitness world by storm. The concept of HIIT training is built around the idea that the intensity of a workout is more important than how long you work out. Although it’s clear that HIIT training has health and fitness benefits, a recent study points out just how a HIIT short workout can be and still be effective.
Short Workout: One Minute or Forty-Five?
If you could work out INTENSELY for one minute versus doing 45 minutes of moderate-intensity exercise, like cycling or walking briskly on a treadmill – you’d take it, wouldn’t you? The only caveat is that one minute has to be an all-out effort. You’ll work hard but the payoff is you’ll spend less exercising. In fact, a recent study showed one minute of all-out effort may offer the same benefits as 45 minutes at a lesser intensity. Pretty amazing, huh?
Researchers at McMaster University in Ontario put high-intensity interval training to the test. They divided 25 previously sedentary men into three groups. One group did 45 minutes of moderate-intensity cycling on an exercise bike. A second group did a short HIIT routine consisting of 20 seconds of all-out effort on an exercise bike followed by two minutes of pedaling at a leisurely pace for recovery.
They repeated this sequence three times for a workout that took a total of 10 minutes and consisted of only one minute of intense exercise. (20 seconds x 3) Both groups did a 2-minute warm-up beforehand. A third group, the control group, did nothing. The men made no changes to their diet or sleep schedule that might have impacted the results.
The participants repeated their designated workouts three times a week for a total of 12 weeks. By the end of the study, the first group had pedaled a grand total of 27 hours compared to 6 hours for the HIIT group. Surely, the second group after all of that pedaling made greater fitness gains. Nope!
In fact, the two groups made virtually identical gains. Their endurance improved by 20% in both cases and their muscles showed adaptations consistent with better endurance – increased mitochondria, mitochondrial enzymes etc. Plus, both groups enjoyed improvements in insulin sensitivity, showing short periods of high-intensity exercise are good for your metabolic health.
This isn’t the first study to show that HIIT training improves exercise endurance. The difference is this study ran a full 12 weeks while most HIIT studies are shorter. In a previous study structured the same way, 20 seconds of intense exercise followed by two minutes of light exercise three times through, experienced on average, a 12% improvement in endurance but this study only lasted 6 weeks. Participants also enjoyed another perk – a drop in blood pressure. Since this study was shorter, you’d expect the endurance gains to be less.
There’s more good news if you hate moderate-intensity cardio. Some studies show GREATER improvements in aerobic capacity with HIIT training relative to moderate-intensity cardio. Plus, high-intensity interval training can boost your anaerobic fitness. Through HIIT training, you increase your anaerobic threshold, meaning your body deals better with the build-up of lactic acid and drop in pH that transpires during an intense workout.
The pay-off is you become adept at doing activities that use fast-twitch muscle fibers like sprinting, plyometrics, and high-intensity resistance training. In fact, HIIT training recruits mostly fast-twitch muscle fibers, the type associated with strength and power, whereas moderate-intensity cardio mainly activates slow-twitch fibers. Yet you’re still getting improvements in exercise endurance. So, HIIT short workout training offers a wide array of health and fitness benefits.
Short Workout: How about Fat Loss?
So, high-intensity interval training is quick and effective for building endurance but what about fat loss? Some, but not all, studies show HIIT short workout training is more effective for fat loss, particularly the loss of belly fat. The reason? It may be the fact that high-intensity interval training creates a greater release of hormones like growth hormone, testosterone, and catecholamines that aid in fat loss. Higher intensity exercise creates an after-burn where your metabolic rate is higher for hours afterward as your body ramps up its energy use to help restore homeostasis. The extra calorie burn works in your favor when you’re trying to lose fat.
Plus, long periods of aerobic exercise can elevate your cortisol level. That’s not what you want since cortisol breaks down muscles and suppresses your immune system. If it’s consistently elevated, cortisol can lead to fat storage around the waist and tummy. Although the stress of HIIT training also leads to a transient rise in cortisol, anabolic hormones like growth hormone and testosterone go up too and this compensates for catabolic effects of cortisol. In addition, HIIT sessions are shorter and are less likely to lead to sustained elevations in cortisol.
Short Workout: Perfect for the Time-Challenged
What most people love about HIIT training is that it’s time expedient. Some days you may have time for an hour-long workout but when you don’t, high-intensity interval training is your ticket. Even if you have plenty of time to work out, ramp it up a notch and enjoy the challenge that HIIT training offers. You can adjust the length of the active and rest intervals based on your goals and your fitness level. Of course, you’ll also want to do strength training. HIIT workouts aren’t a substitute for working your muscles against resistance.
There a lot of ways to structure a high-intensity interval training workout but they all offer benefits that you don’t get from moderate-intensity aerobic exercise, mainly the after-burn that you get and the fact that you’re improving aerobic and anaerobic fitness. HIIT training is tough but many people find it to be more enjoyable than standard cardio since you’re not doing the same activity for 30 minutes or longer. If you haven’t tried it, you owe it to yourself to give it a try. It’s not a workout to do every day – give yourself at least 48 hours of rest between HIIT workouts.
References:
New York Times. “1 Minute of All-Out Exercise May Have Benefits of 45 Minutes of Moderate Exertion”
Shape Magazine. “A 1-Minute HIIT Burst Can Transform Your Workout!”
Poloquin Group. “Is Aerobic or Anaerobic Training Best for Getting Rid of Belly Fat?”
Skoluda, N., Dettenborn, L., et al. Elevated Hair Cortisol Concentrations in Endurance Athletes. Psychoneuroendocrinology. September 2011.
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High-Intensity Interval Training: How Intense Does It Have to Be?
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