Fitness
Benefits of zone 2 cardio training for glucose health
By Gary Scheiner MS, CDCES
Published: Apr. 15, 2025
4 min read
The content in this article should not be taken as medical advice. Please consult with your healthcare provider regarding your individual health needs.
Usually, when we bring up target ranges, we’re referring to glucose levels. But here’s another type of target to think about: your exercise intensity zone.
Just like keeping glucose within an optimal range is important, exercising with the ideal level of intensity is equally as important for your body, and even impacts glucose regulation. Exercise intensity can be divided into three zones:
- Zone 1: Light
- Zone 2: Moderate
- Zone 3: Intense
Being in the right zone can make or break your workout. Exercising at too low an intensity (zone 1) may fail to produce the results you’re looking for, though still beneficial for your glucose health. Exercising at too high an intensity (zone 3) can lead to pain or injury. High intensity workouts can also cause the body to produce stress hormones, which can raise glucose levels.
Benefits of zone 2 cardio training
Keeping yourself in zone 2 during a workout is associated with a number of important benefits, including:
- Weight loss
- Improved stamina
- Lowering of glucose levels
- Reduced blood pressure and cholesterol
- Stress relief
Energy expenditure plays an important role during exercise. In zone 1, the body only burns a few more calories than it burns at rest. In zone 2, the body burns more calories, mostly from fat. In zone 3, we burn more calories per minute, but the workout is not likely to last very long and the energy comes primarily from glucose (sugar). Because of all this, zone 2 is best for those trying to lose weight.
Measuring your exercise zone
There are several ways to measure your exercise intensity, and some are more complex than others. If you know your maximum heart rate (which is approximately 220 minus your age), you can try to stay within 65% to 75% of that number.
For example, if you’re 40 years old, your estimated maximum heart rate is around 180 beats per minute (220 minus 40). Zone 2 falls between 65% and 75% of your maximum heart rate —about 117 to 135 beats per minute.
Of course, this requires taking your pulse (or using a heart rate monitor) during your workout. It also assumes that the “220 minus age” formula is appropriate, which isn’t always the case. Many people who take medication for blood pressure or heart conditions have lower-than-normal maximum heart rates.
Another approach to determining your zone is to rate how hard you’re working on a scale of 0 to 10. Using the Rating of Perceived Exertion (RPE) chart below, the goal is to be in the 4 to 6 range: slightly challenging to slightly vigorous. This places you squarely in exercise zone 2.
Rating of Perceived Exertion (RPE)
Perhaps the most practical method for ensuring you’re training in zone 2 is to apply the “talk test”:
Zone 1: You can sing easily
Zone 2: You can talk in short sentences, but singing is difficult
Zone 3: Talking feels like a struggle
Zone 2: You can talk in short sentences, but singing is difficult
Zone 3: Talking feels like a struggle
If you find yourself in zone 1, try picking up the pace a little bit. Zone 3? Time to slow down a bit.
Exercise that meets you where you are
The real beauty of exercise according to your zone is that each person’s intensity level is customized to their own ability. For example, someone who is new to exercise (and perhaps with reduced stamina) may be able to reach zone 2 cardio by simply walking at a slow pace. Someone who already exercises regularly may have to run pretty fast to reach zone 2. But as long as they’re both in the same zone during their workout, the runner and the walker are getting the same benefits.
Over time, as your level of physical fitness improves, you’ll need to make your workouts more challenging to stay in zone 2. With training, you’ll be able to move faster, lift more weight, and work against greater resistance without raising your level of exertion. When that happens, congratulate yourself. It means you’ve made real progress.
The production of this article was sponsored by Stelo by Dexcom.
References:
The Athlete’s Guide to Diabetes. Colberg, Sheri R. Champaign, IL: Human Kinetics, 2020.
Author profile
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Gary Scheiner MS, CDCES
Gary Scheiner is the owner and Clinical Director of Integrated Diabetes Services, a practice specializing in intensive insulin therapy and advanced education for children and adults throughout the world.