Critics of steady-state cardio exercise are right about a few things. It isn’t a cure-all. Beyond a low baseline level, you won’t build much strength, power or muscle. And contrary to what many people believe, you won’t burn an appreciable amount of fat, either. Exercisers in a 2009 study conducted by researchers at Queensland University of Technology in Australia who did steady-state cardio five times a week for 12 weeks lost only 7 pounds on average — and nearly half of them lost less than 2 pounds. Steady-state cardio is also repetitive. Jog for 30 minutes and you may take as many as 5,000 steps. To some exercisers, that’s meditative; to others, it’s a bore.
It may also be risky, says sports medicine physician Jordan Metzl, coauthor of The Exercise Cure (Rodale, 2013). “The more you perform a single-movement pattern, the more you load up one area of the body, and the more likely you are to get injured.”
Still, for a low-key workout that reduces your stress level and improves recovery while delivering general health and an efficient aerobic engine, old-fashioned steady-state cardio is underrated and tough to beat.
THE HYPE OVER HIIT
Interval training — in the form of sprints, shuttle runs, and timed lap swimming — has been a staple among athletes for at least a century. More recently however, casual exercisers have caught on to its benefits as well. “Back in 1992, it was understood that if you wanted to be lean and healthy, you had to do cardio — hours of it,” recalls fitness journalist Lou Schuler, coauthor of The New Rules of Lifting Supercharged (Avery, 2012).
Starting in the late ’90s, however, a number of studies, including one by Japanese researcher Izumi Tabata, who popularized the Tabata Protocol, suggested that short, intense interval workouts may produce results similar to longer, slower cardio workouts in a much quicker time period.
Soon thereafter, Schuler and many other fitness journalists began touting the benefits of HIIT.
Does HIIT live up to the hype? In some respects, yes. “If you’re trying to lose fat, it’s pretty clear that HIIT is a more effective tool than long-distance cardio,” Robertson says. Physiologists have yet to develop a full explanation for why this is, but one reason may be the so-called after-burn effect, in which the metabolism remains elevated for hours — and sometimes even days — after an intense workout!
The how isn’t important for coaches like Robertson and Mike. They just know that when a client wants to lose fat fast, HIIT is one of the best tools. One 1994 study at Laval University in Quebec, Canada, found HIIT was nine times more effective for losing fat than steady-state cardio.
Regular HIIT workouts also improve your ability to withstand the rigors of other types of interval training, adds Mike. The aching sensation in your muscles that accompanies a hard sprint (which results from burning carbohydrates for fuel) becomes less intense and subsides more quickly over time, allowing you to work at a higher intensity with less rest. Your capacity to transition smoothly from burning fat (before your workout and during rest periods) to burning carbohydrates (during your work intervals) and back again — known as your “metabolic flexibility” — improves with HIIT, as well. Together, these metabolic benefits bolster health and athletic performance, particularly in sports requiring short bursts of all-out effort interspersed with periods of reduced effort, such as basketball or martial arts.
All these benefits result from time-efficient workouts that are much shorter than your average lower-intensity cardio session. Just six HIIT workouts performed over two or three weeks, each lasting just a few minutes, produced measurable improvements in key markers of cardiovascular health, a 2012 study published in the Journal of Strength and Conditioning Research found. Regardless of your goals, it’s hard to argue against including at least some HIIT in your routine.
But just because some HIIT is beneficial doesn’t mean it’s all you need — or that more HIIT will necessarily give you more benefits. “One of the biggest misconceptions about HIIT is that it develops the aerobic system and the anaerobic system equally,” says Robertson. “But aerobic and anaerobic exercise actually place very different demands on your heart and your muscles.” Since the advent of HIIT, Robertson says he’s seen more athletes who are anaerobically fit but aerobically weak. “We’re talking division in athletes with resting heart rates in the high 70s or low 80s” — the equivalent of a couch potato’s. “They’re fast and strong, but they gas out after just a few minutes on the field.”
Beginners may see some improved aerobic functioning with HIIT, concedes Robertson, but they quickly reach a point of diminishing returns. “After four to eight weeks,” he says, “you’re just grinding your gears and putting a lot of strain on your system at the same time.” Mentally and physically, he says, “high-intensity training can be downright brutal.”
A steady diet of HIIT can also stimulate a near-constant flight-or-fight response from your autonomic nervous system, says Robertson, resulting in a host of anxiety-like symptoms: racing heart, sweaty palms, difficulty sleeping, and an inability to sit still or focus. Over time, this hyper-vigilant state can impair recovery. “With HIIT, you have a higher probability for overreaching and overtraining, especially if you’re doing strength training as well,” Mike says.That’s a recipe for aches and pains in the short term, stalled progress and burnout in the medium term, and injury in the long term.
PUTTING IT ALL TOGETHER
So steady-state cardio may deserve a second look — even if some exercisers find it unexciting. And though HIIT is clearly effective in the short run, it can grind you down if you keep it up.
Given these pros and cons, what’s best for your workout?
The answer is a resounding . . . it depends. Beginners’ needs are different from those of competitive athletes. “Before you can decide on what type of cardio is best, you need a goal,” Weingroff says. “Then, the program you choose should reflect a balance of getting good at what you’re not good at and even better at what you are good at.”
Gym-goers can be extremists. They don’t just like their group cycling classes or weightlifting workouts, they love them — so much that they’ll keep doing them even long after the workouts have stopped making them feel, look, or perform better. “The biggest thing we need to respect,” says Robertson, “is that it’s not one extreme or another. There’s a time and a place for both low- and high-intensity training. You just have to figure out how to put it together into one seamless, integrated package.”
The first step? Recognize that the best workout program for you may very well be the one you’re not doing right now.
Source: Andrew Heffernan