6 Top Reasons to Try Circuit Training

In a 2018 study from the Journal of Exercise Rehabilitation, university-age participants who completed a 12-week circuit training programme that featured resistance exercises, such as squats, crunches, lunges and push-ups saw improvements in all moves (meaning participants were able to execute more repetitions and with less fatigue in the allotted amount of time). This is defined as muscular endurance, or the capacity of muscles to contract until fatigue.

(Related: Does HIIT Really Work? The Benefits of HIIT Workouts)

As strength-focused circuit training involves alternating between most, if not all, of the major muscle groups, exercisers are often able to effectively train their entire bodies—without repeated sessions.

"Circuit training may be a bit more time-efficient for exercisers who want to get a full-body workout in a relatively short period of time—say, 30 to 40 minutes", Machowsky said. "Also, some people may enjoy the faster-paced nature of circuits".

Although muscular endurance is often a hallmark perk of circuit-style training, the workout can also bring improvements in both muscular strength and muscular hypertrophy (when a muscle increases in size), Machowsky said.

A systematic review of studies surrounding strength training and older adults, for example, found that regular participation in strength-based circuit training could effectively increase strength. That was an important finding for the subject group, as increased muscle strength in older adults is associated with a reduction in fall risk and other injuries.

In HIIT circuits, exercisers may receive health benefits on a metabolic and vascular level too, science shows. In the previously noted 2018 study from the Journal of Exercise Rehabilitation, participants also saw improvements to their cholesterol and triglyceride levels by the end of the trial.

Another study, published in a 2011 issue of the Journal of Applied Physiology, noted that HIIT circuit-style training could potentially help decrease exercisers' insulin resistance, or their risk factor in developing type 2 diabetes.

Even better news: It doesn't take much HIIT circuit training to reap the benefits. The study noted that as few as eight minutes of all-out exertion (not necessarily for the full eight minutes at once) could help reduce insulin resistance.

A 2017 study from Frontiers in Physiology found that there's a strong likelihood cardiovascular fitness will increase from regular participation in HIIT-based circuits. During the nine-week study, female participants performed three weekly sessions of mainly resistance exercises with short treadmill sprints, and those exercisers were able to improve their overall oxygen uptake ability.

Circuit training might not necessarily be better than other forms of exercise at improving certain health and fitness markers—but it can sure be unique and fun, said Missy Berkowitz, a NASM-certified personal trainer.

"Circuit training keeps workouts interesting", she said. To boot, many popular group fitness classes use a circuit style of training—and studies show that social support and interaction alone can spur athletes to show up to workouts continuously.