Circuit training is especially popular these days, and with good reason. Circuit training classes tend to leverage things like group encouragement, and peer pressure, to keep your working hard. Classes usually involve brief, intense bouts of activity, combining both aerobic and resistance forms of exercise, with only brief intervals of rest.
The benefits are abundant, but the ability to fit in a great deal of exercise in a relatively short time stands out. Circuit training tends to emphasize the concept of high intensity training (HIT). Research continues to mount that this form of intense exercise training may be especially useful for effectively lowering various heart disease risk factors and enhancing “muscular performance”.
HIT has garnered some attention in recent years, because it promises to deliver “maximum results with minimum investment” on the part of the person doing these intense workouts. At least, that’s the conclusion of a study published in ACSM’S Health and Fitness Journal. Published by the American College of Sports Medicine, the study explained the philosophy behind this new approach to fitness.
Even elite athletes operate under severe time constraints, and may struggle to schedule sufficient time each week to fit in traditional bouts of aerobic and resistance training. Typically, athletes must perform up to 150 minutes per week of moderate intensity exercise, or 75 minutes of vigorous intensity exercise to maintain aerobic fitness. Obviously this approach to physical fitness requires considerable time.
High Intensity Circuit Training (HICT) was developed in an attempt to maximize results and minimize time spent working out. Rather than relegating each form of exercise to a different day of the week, HICT incorporates both aerobic and resistance training into the same rapid, intensely demanding workout. These workouts typically raise the heart rate significantly, and rest times between intervals of effort are reduced, further maximizing gains.
A Movement in the Making
According to the above-mentioned report, modern circuit training was developed at the University of Leeds, in England, in the early 1950s. Despite its inception more than 60 years ago, this form of training is only now gaining wide popularity and acceptance. There’s mounting evidence to suggest that HICT works. Not only does it deliver more dramatic physical fitness gains in less time, it also improves various markers of cardiovascular and lung function fitness. One recent study concluded that performing high-intensity interval training three time per week, for three months, yields improvements in “tradition cardiovascular disease risk factors, oxidative stress, inflammation, and insulin sensitivity.”
Another recent study, using both male and female subjects who engaged in HICT using only their own body weight for resistance, documented significant improvements in muscle endurance among both genders, and improvements in aerobic fitness among females. Perhaps most tellingly, a 2014 study recruited a small number of sedentary, obese men and assigned them to perform HICT for four weeks. Despite engaging in exercise for just six hours over the course of those four weeks, the men experienced “significant improvement in biochemical, physical, and body composition characteristics…” Although significant weight loss did not occur in so short a period, participants did experience a drop in the percentage of body fat, and improvements in insulin levels.
“The improvement observed in key health markers induced by our six-hour high-intensity exercise paradigm compares well with studies results using 4 to 8 times longer traditional aerobic, resistance, and circuit training programs (i.e., lasting 12–48 hours),” investigators wrote.
There’s a reason interval training classes are gaining in popularity. In some ways they reflect our busy modern times: we’re all interested in maximizing our results in the least amount of time. And HICT evidently delivers. By combining both aerobic and resistance training, it helps build aerobic function, while improving muscle strength and function. These workouts are intense, but when you’re serious about fitness, and time is at a premium, they just might be your best option.