Aquatic HIIT: Increasing Fitness at Any Level
While High Intensity Interval Training (HIIT) is often used in training high level athletes, it has been shown to provide benefits for individuals at any age or fitness level. Why? In short, these workouts provide health benefits while saving time.
Bursts of intense training sandwiched between short rest periods, repeated for 15 minutes or so shave time off an otherwise lengthy cardio routine and, studies show, shave inches off a waistline. HIIT also boosts heart health, metabolism and caloric consumption. The concept of training at high intensities for short intervals is even the principle concept propelling entire gym franchises around the country.
HIIT has been around for at least 100 years and probably much, much longer. Scandinavian runners in the 1900s trained for the Olympic games using intermittent bursts of speed and rest to increase cardio ability and build muscle.
Aquatic HIIT (AHIIT)
Not everyone can participate in land-based HIIT, for a host of reasons, including chronic pain, obesity or injury. In these situations, the buoyancy and support water provides, coupled with a variable-speed underwater treadmill, can be the right modality for many who would otherwise not tolerate high intensity activity.
In 2015, Elizabeth Nagle, PhD, Mary Sanders, PhD, and Barry A Franklin, PhD, published a metanalysis in the American Journal of Lifestyles Medicine entitled “Aquatic High Intensity Interval Training for Cardiometabolic Health: Benefits and Training Design.” The authors included in their analysis a table showing five studies around aquatic HIIT and studies’ key findings. (show table)
The Research Behind It
In 2006, Broman found that healthy elderly women engaging in deep-water running HIIT twice a week for eight weeks increased oxygen consumption rates (a sign of increased fitness), achieved a lower resting heart rate and lower sub-maximum heart rate. Another study, Martin, 1987, with sedentary middle-aged men and women swimming and participating in land-based circuit training three times a week for 12 weeks showed increased oxygen consumption and decreased heart rate for participants.
In 2014, Mohr demonstrated that sedentary, premenopausal women with mild hypertension could also benefit more from AHIIT than moderately-paced aquatic exercise. Rebold’s study, 2013, took young, healthy men and women into shallow water and, while running under water twice a week for eight weeks, showed an increase in mean aerobic power and flexibility. Wilbur learned in 1996 that young, trained male runners engaging in deep-water running HIIT achieved the same oxygen consumption gains as those in a land treadmill HIIT program, and without the wear and tear on their joints and feet.
Another study in 2014, from Utah State University showed benefits of HIIT training on an underwater treadmill for adults with osteoarthritis. This study observed that patients with osteoarthritis (OA) reduced joint pain and improved balance, function and mobility after participating in a 6-week aquatic treadmill exercise program that incorporated a balance and HIIT training component.
Maybe one of the more important discoveries was that adherence to the exercise was exceptional and no participants reported adverse effects, suggesting that aquatic treadmill exercise that incorporates high-intensity intervals is well-tolerated by patients with OA and seems to be effective at managing symptoms of OA.
A Suggested AHIIT Workout
Physical therapists can modify land-based HIIT for AHIIT or develop new programs depending on their patients’ abilities and fitness level. Below is a suggested program for those in moderate physical shape. Either stick with round one or move through the three rounds. Regardless, they should spend about 20-30 minutes in the pool.
HIIT will endure as a hot topic in the fitness and training universe as studies continue to show its worth and fitness seekers continue to feel and see, first hand, its positive effects. And as more folks gain access to underwater treadmills and other aquatic environments, AHIIT will continue to aid those with a desire to unload their joints and utilize water’s natural properties to condition and heal.