Is Exercise More Difficult with Type 2 Diabetes?
We will answer this question shortly.
But first, when talking about whether exercise is more “difficult” for type 2 diabetics, the question is really referencing exercise intensity. There are a number of ways to measure/monitor exercise intensity. We prefer to use Ratings of Perceived Exertion (RPE).
The question refers to a scenario like this:
Given two individuals where everything is the same (age, gender, height, weight, etc…) when performing the same type of exercise, is it more difficult for the type 2 diabetic?
The answer to this question: Yes (in general)1
To illustrate, let’s say the exercise we referred to above is walking at 3 mph. The typical non-diabetic might rate the intensity of this activity at a 3 or 4 on a 10-point RPE scale, while the typical type 2 diabetic might rate it a 5 or 6 on the same scale.
Since RPE is a measure of intensity and 5 or 6 is higher than 3 or 4, we would have to say that, in general, type 2 diabetics have more difficulty with the same activity than non-diabetics.
Why is exercise harder for Type 2 Diabetics?
Look no further than resting metabolism. Metabolically unhealthy (which is what type 2 diabetics are) have a higher respiratory quotient at rest when compared to metabolically healthy individuals. This means type 2 diabetics are using a larger proportion of carbohydrates as a substrate to produce energy. Further, substrate utilization predicts intensity: The more carbohydrates, the higher the intensity.
For type 2 diabetics, this means that even at rest they are producing energy differently than non-type 2 diabetics. And when we change the intensity, like walking at 3 mph for example, this relationship holds true. So they continue to operate at a higher intensity, which is what makes exercise more difficult for type 2 diabetics.
If this is the case, how should we approach exercise and exercise intensity for type 2 diabetics?
Type 2 Diabetics and Exercise
From a metabolic perspective, type 2 diabetics operate at a higher intensity level in comparable exercise because their ability to use fat as a substrate to produce energy has been compromised. (See this for an example). In other words, the average type 2 diabetic has difficulty in using fat to produce energy.
This difficulty in using fat to produce energy makes it harder for type 2 diabetics to lose weight.
This should be addressed first.
Improving metabolic flexibility in type 2 diabetics
In the literature and even within both The Academy and the HPI Diabetes Academy, we refer to this as metabolic flexibility: The ability of the metabolism to switch between substrates (carbohydrates or fats) to produce energy. For someone lacking metabolic flexibility, their ability to switch is compromised. Since type 2 diabetics have difficulty in using fat to produce energy, their metabolic flexibility is compromised.
So the first objective should be to “un-compromise” them by improving metabolic flexibility.
The two best approaches to fixing this are with food and exercise. Since this article is about exercise, we will omit the food part.
We only have two recommendations for exercise: low-intensity and/or high-intensity. Both are effective for different reasons.
Low intensity is effective because it forces the body to get better at using/burning fat during the exercise session. There are a couple of caveats, however:
- The intensity must be lower than normal, due to the compromised ability to burn fat.
- To be most effective, duration must be longer than 30 minutes – the longer the better. As it takes time for the body to fully get into a fat burning mode, shorter duration activities are not as helpful.
High-intensity exercise is effective because it helps improve the body’s ability to burn fat outside of the session. Earlier, we mentioned that type 2 diabetics have a higher respiratory quotient at rest, which means they are using a higher proportion of carbohydrates to produce energy. As the body adapts to high-intensity exercise, it starts fixing this problem. The end result is a lower respiratory quotient, which means the body is using a larger percentage of fat to produce energy at rest.
On a related note, this is why we aren’t big fans of jogging for most people until they get to a point where metabolic flexibility has improved.
Yes, exercise is more difficult for type 2 diabetics
But this problem can be fixed with an appropriate exercise prescription, one that improves the body’s ability to burn fat during exercise and at rest.
This will result in the increased ability to perform comparable exercise at a lower intensity.
1We say in general, because there are always exceptions and this refers to the average.