When you’re pressed for time, a high-intensity exercise session gives you fitness benefits in the shortest time possible. Research shows super-short Tabata workouts, eight 20-second cycles of intense exercise separated by 10 seconds of rest, is enough to offer cardiovascular benefits. They’re also a real fat-scorcher! It’s clear that you can improve your fitness level with short workouts as long as you keep the intensity level high. Until now, researchers haven’t really known what’s going on at the molecular level that makes high-intensity exercise so effective. Now, a new study sheds some insight into how high-intensity exercise gets you into shape.
How High-Intensity Exercise Exerts Its Benefits
Researchers at the Scripps Research Institute in Florida recently studied a protein called CRTC2. This protein appears to be activated during high-intensity workouts called CRTC2. To study this protein, researchers used genetically-modified mice bred to express CRTC2. When the mice expressed this protein, they gained, on average, 15% muscle mass. In addition, their body showed metabolic changes that go along with exercise including increased glycogen stores.
Could CRTC2 activation be the reason short but intense workouts are so effective? When you exercise at a high intensity, it maximally “turns on” your sympathetic nervous system. This boosts the release of “flight or fight” hormones like adrenalin and norepinephrine that bump up your heart rate and increase blood flow to your muscles. As a result, your muscles can get more oxygen and nutrients. This happens during moderate intensity exercise too but to a lesser degree. Makes sense since high-intensity exercise is more stressful on your body.
Researchers don’t believe input from the sympathetic pathway is enough to account for the 15% increase in muscle mass the mice experienced. CRTC2 also seems to be responding to signals from another pathway, the calcium pathway. CRTCw seems to use a combination of inputs from the sympathetic nervous system and calcium pathways to stimulate muscle growth in muscles that are actively contracting.
Although human research is still needed, researchers hope they can find a way to enhance the activity of CRTC2 so people can get the fitness benefits of exercise without doing a high-intensity workout. Of course, there are drawbacks to getting CRTC2 as a pill or supplement. You’d miss out on other benefits of high-intensity interval training – and there are plenty of them.
Other Benefits of High-Intensity Workouts
Most studies looking at moderate versus high-intensity exercise from a cardiovascular standpoint show vigorous exercise to be the most heart healthy. Research suggests vigorous exercise is more effective than moderate-intensity exercise for reducing risk factors for coronary heart disease and for preventing atherosclerotic disease. Unlike moderate-intensity exercise, high-intensity workouts challenge both your aerobic and anaerobic energy systems, offering optimal cardiovascular benefits. Of course, you don’t want to do a high-intensity workout if you already have heart disease until you clear it with your doctor.
High-intensity exercise may also be better for reducing body fat. That’s because high-intensity exercise maximally activates fat-burning hormones like growth hormone, testosterone and adrenalin more than working out at a lower intensity. High-intensity workouts also raise your core body temperature more. Because you exercise above your anaerobic threshold during high-intensity exercise, your muscles build up more lactic acid. All of these things force your body to work harder and expend more energy during recovery. Therefore, you get more of an afterburn with high-intensity exercise. Due to the afterburn, your metabolism is higher for hours after you finish. High-intensity exercise also appears to be better for abdominal fat loss than moderate-intensity exercise.
High-intensity exercise may also be better from a motivational standpoint. It’s easier to get motivated to do a shorter workout and the challenge of working out at a high intensity can be rewarding too. Plus, there are so many ways to get a high-intensity workout.
Balance High-Intensity Exercise with Lower Intensity Workouts
More isn’t better when it comes to high-intensity exercise. The beauty of high-intensity training is you can get benefits without spending a lot of time working out. Doing a high-intensity workout every day could quickly lead to overtraining, overuse injuries or burnout. Balance high-intensity training with lower intensity “recovery” workouts like yoga, a low-impact circuit or step workout to let your body recover. If you’re trying to lose a significant amount of weight, you may benefit from moderate-intensity exercise sessions that last 45 minutes to an hour like a spin or kickboxing workout. There’s no reason why you can’t incorporate both into your workout plan. High-intensity workouts are ideal for those days you have limited time to exercise or any time you want to challenge yourself to the max.
The Bottom Line?
Don’t miss out on the benefits of high-intensity exercise. There are a variety of ways to structure high-intensity intervals to maximize anaerobic and aerobic benefits. High-intensity exercise is sure to improve your fitness level and help you burn more fat. Take advantage of the benefits vigorous workouts offer.
Medical News Today. “Scientists Unravel the Molecular Secret of Short, Intense Workouts”
Medicine and Science in Sports and Exercise 39 (4): 665-71. doi:10.1249/mss.0b013e3180304570. PMID 17414804.
J. Obes. 2011. “High-Intensity Intermittent Exercise and Fat Loss_
Medscape Family Medicine. ‘Effect of Exercise Training Intensity on Abdominal Visceral Fat and Body Composition”
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