Is CrossFit An Effective Workout For People With Diabetes?
More than 10% of the U.S. population has diabetes, according to the Centers for Disease Control and Prevention. An overwhelming majority of those diabetes cases are type 2 diabetes, which typically develops after age 45. The CDC recommends managing type 2 diabetes through diet and exercise, but what kind of exercise is most beneficial?
A 2010 position statement from the American College of Sports Medicine and the American Diabetes Association published in Diabetes Care gave exercise guidelines for people living with type 2 diabetes. It suggested at least 150 minutes of moderate aerobic exercise each week. This moderate exercise could include walking or any exercise that gets the heart rate to 40 to 60% of VO2 max. This exercise should be spread throughout the week to keep the blood sugar levels steady. The statement also recommended resistance training at least twice a week, preferably three times a week, working all the major muscle groups of the body.
CrossFit is a high-intensity exercise program that blends functional strength training with high-intensity workouts (via NBC News). Although its devotees swear by its fitness benefits, how well does CrossFit manage diabetes?
CrossFit's effects on insulin sensitivity
A 2018 study in Experimental Physiology recruited 13 people with type 2 diabetes to participate in CrossFit for six weeks. The participants' average age was 53, and the average BMI was 34.5. Each participant exercised with a CrossFit coach three times a week, and all the participants did the same workouts. For example, one workout was called the "fight gone bad," which is one minute each of rowing, wall ball toss, deadlift high pulls, push presses, and box jumps for three sets.
After six weeks, the researchers compared the body composition, blood pressure, insulin sensitivity, and cardiometabolic risk factors with the participants' baseline stats. The participants decreased their diastolic blood pressure, total fat mass, and triglycerides. They also increased their insulin sensitivity by 15% and lowered their risk of cardiovascular disease. The researchers concluded that because CrossFit combines aerobic conditioning and strength training, it's an efficient way for people with type 2 diabetes to manage their condition.
How high-intensity interval training helps manage diabetes
Before the CrossFit study was published, a 2015 article in Diabetes Spectrum suggested that high-intensity interval training (HIIT) might be more beneficial than moderate-intensity exercise (like walking) for managing type 2 diabetes. Although moderate activity is safe for people who have a normal, active lifestyle, people with type 2 diabetes need a stronger cardiovascular boost to produce the necessary benefits for their health. The article reviewed other research studies that found that people with type 2 diabetes who were left to walk at their own pace didn't walk fast enough to manage their condition. Instead, the article suggested that supervised workouts that incorporate vigorous intensities might work better. This might include faster bursts of intensity for 30 to 60 seconds every few minutes of moderate-intensity workouts such as walking.
A 2018 review in Aging Clinical and Experimental Research compared moderate-intensity exercise programs with HIIT. HIIT works better than moderate intensity in improving cardiovascular fitness in people with type 2 diabetes. Although some studies found that HIIT can reduce BMI, body weight, and blood glucose, many of the studies lacked quality evidence to support their claims. Therefore, the review concluded that stronger experimental studies with more people were needed.