High-Intensity Interval Training for Diabetes
By Erin Davis
You notice there’s a buzz around “HIIT” workouts. Your gym is offering classes and you see it suggested online. But what is it? Is it safe for someone with diabetes?
Tired of the treadmill or bike? Don’t have time for an hour-long gym session? You don’t have to force yourself to do another boring workout. Keep it fun by choosing exercises you enjoy or that challenge you, like HIIT.
High-intensity interval training, HIIT for short, is a workout involving brief bursts of activity with active recovery periods. Because of the intensity, the workouts are short, which is appealing for those who are pressed for time.
As the name “high-intensity” implies, you push yourself hard during those bursts. If you’ve seen videos of pros doing HIIT, you might wonder if it’s too intense. Fortunately, there’s a way you can tailor HIIT to meet your fitness level and health goals. Here’s what you need to know about HIIT if you have diabetes.
Is HIIT as effective as other forms of exercise?
Are short workouts enough to meet exercise recommendations? According to the Physical Activity Guidelines for Americans, they can be. While at least 150-300 minutes of moderate-intensity activity is suggested weekly, only 75-150 minutes of vigorous-intensity activity is needed.
The key to HIIT’s effectiveness and time savings is the intensity. During the active periods, you have to be exercising at or near peak effort. You’re working vigorously – that means unable to keep up a conversation without stopping to take a breath.
One way to do this is to use the perceived rate of exertion as a guide. This is a scale of 6-20, where 6 is no exertion and 20 is max exertion. Exertion is subjective and unique to you. As your fitness improves, you’ll be able to do more difficult moves at faster speeds with less exertion. Aim for a rate of 13-15 to start.
Sample HIIT exercises
The great thing about HIIT is its versatility. It can also be done at home or in a gym. You can perform HIIT exercises with your body weight, dumbbells, kettlebells, treadmill, bike, rowing machine, bands, or the elliptical.
Here are a few examples of a HIIT workout:
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Jump rope for 30 seconds and rest for 30 seconds; repeat as many times as possible
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Kettlebell swings for 10 minutes; swing for 45 seconds, rest for 15 seconds
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Dumbbell squats for 20 seconds, rest for 10 seconds; repeat until you can’t do it anymore
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Burpees (exercise where you squat, do a pushup, and then jump in the air) for 20 seconds, rest for 30 seconds; 10 rounds
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Pushups for 30 seconds, rest for 10 seconds; six rounds
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Sprint on treadmill for 12 minutes; run for 20 seconds, rest for 30 seconds
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Brisk walk for 40 seconds, slow down for 40 seconds; repeat for 20 minutes
Benefits of HIIT for diabetes
Besides saving time and adding variety to your physical activity routine, HIIT has multiple benefits for someone with diabetes.
Glucose control
Looking to improve your time in range? HIIT sessions have been found to have a greater glucose-lowering effect when compared to walking on a treadmill. Improved blood sugar levels aren’t just for the young, either – HIIT also improves blood sugar in older adults.
“Intense exercise can have lasting effects up to 48 hours into recovery on improved glucose,” said Toby Smithson, registered dietitian and certified diabetes care and education specialist.
Improved body composition
Sure, resistance exercises like weight lifting promote muscle growth, but HIIT may also give you gains. HIIT increases muscle capacity, thereby increasing muscle mass. Along with muscle growth, HIIT may also reduce body fat percentage.
The reduction in body mass index, waist circumference, and body fat are similar and sometimes better with HIIT when compared to moderate-intensity continuous exercise.
Insulin sensitivity
Regular exercise can improve insulin sensitivity over time. This means that the body becomes more efficient at using insulin to transport glucose into cells, potentially reducing the overall need for insulin.
At the same time, HITT can initially lead to an increase in insulin requirements. This is because the body may require more glucose to fuel muscles during activity. Responses to exercise can vary among individuals.
Heart health
Incorporating HIIT into your routine may improve heart function, blood pressure, heart rate, and overall cardiovascular fitness. Even doing HIIT once per week may yield heart health benefits.
Is it safe for people with diabetes?
Studies have shown that not only is HIIT usually safe for people with diabetes, but it may be an option for those with a tight schedule or a fear of hypoglycemia.
Before jumping into a HIIT workout, there are special considerations, especially if you’re taking insulin or other glucose-lowering medications. That, and everyone responds differently to exercise.
“While using a HIIT program can show benefits to blood sugar management by burning glucose and improving insulin sensitivity, I have also experienced rises in my blood sugar,” said Smithson, who lives with diabetes. “The rise can occur after the adrenaline kicks in as we use our muscles, especially in an intense workout. But I’ve also experienced hypoglycemia during the workout as well as steady blood sugar.”
“HIIT would be best for those with stable blood sugar levels and who have been cleared to participate in moderate to intense exercise. Those who have uncontrolled blood sugar levels, frequent hypoglycemia, or uncontrolled blood pressure would not be appropriate for HIIT,” said Erin Palinski-Wade, a New Jersey-based personal trainer, registered dietitian, and certified diabetes care and education specialist.
If you have diabetes and are looking to add HIIT to your workout routine, it’s always a good idea to consult with your healthcare team to ensure it’s a safe option for them.
If you’re new to exercise, moderate-intensity interval training may be a better option to start. Because there is an increased risk for cardiovascular events, the American Diabetes Association recommends people receive a medical evaluation, which may include an electrocardiogram, before sprinting into vigorous activity.
Tips for getting started
The great thing about HIIT is that it can be personalized to suit your needs and preferences. Here are some tips if it’s your first HIIT workout:
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Be prepared: Make sure you have snacks in case your blood sugar is trending down or is already low. Carrying a fanny pack is a good way to keep snacks close at hand.
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Check glucose levels: For any workout, it’s always a good idea to monitor glucose levels before, during, and after workouts. A continuous glucose monitor (CGM) is a useful tool that may prevent hypoglycemia during a workout. “Keep in mind that CGMs lag in their results. Watching the blood sugar trend on your CGM may be a better indicator than the actual number. HIIT makes everything go faster – glucose depletion, glucagon signaling, and stored glucose release,” Smithson explained.
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Ease into it: High intensity looks different for everyone. Modify your workout to suit your fitness levels and work your way up to more intensive training.
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Play around with the timing: The time of day you exercise can also make a difference in blood sugar levels. Use trial and error to find out what works for you. “For instance, morning exercise may have the residual of above target readings from the dawn phenomenon,” Smithson added.
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Adjust insulin dosing if necessary: HIIT can reduce your insulin demand, so you may need to respond appropriately. If you use an insulin pump, you may need to play around with the timing of suspending pump use, before, during, or after HIIT.
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Stay hydrated: Proper hydration is important to protect from fluid losses that occur during exercise.
The bottom line
HIIT is a cardiovascular exercise session that switches between active bursts and rest. Examples of HIIT exercises include pushups, jump rope, burpees, sprinting, and weight workouts. Training at high-intensity levels can improve fitness, strength, and metabolism.
A big benefit of HIIT is it can be modified to be anything you want it to – and can be done in 20-30 minutes. HIIT exercises are quick, can be done at home or the gym, and have multiple benefits for diabetes including better glucose control, improved insulin sensitivity, and supporting heart health.
Learn more about exercising with diabetes here:
