Logo Sciences du sport

Logo Sciences du sport


Informations sur les Sciences de l'Entraînement Sportif

Type 2 diabetes: Dose-response relationship of cardio on glycated hemoglobin

by A. Manolova | 31 August 2022

sport, health, physical activity, type 2 diabetes, intensity, cardio, cardiovascular, training, volume, dose, disease

For the past 40 years, type 2 diabetes has been steadily increasing worldwide. It is characterized by a chronic elevation of blood glucose beyond the normal range (glycated hemoglobin level above 6.5%). It represents 90% of diabetes cases and some studies estimate that the number of diabetics could increase from 285 million in 2010 to 450 million in 2030, not counting the number of people with pre-diabetes (glycated hemoglobin level between 6 and 6.5%). Type 2 diabetes is often accompanied by micro- and macro-vascular complications. Unlike type 1, type 2 diabetes is mainly the result of the "western" lifestyle, which is itself associated with a sedentary lifestyle, overweight and obesity. If type 2 diabetes generally appeared around the age of 40, it is now increasingly present in young populations.

Physical activity in general and sport in particular have beneficial effects on the prevention of type 2 diabetes and on the improvement of the health status of people already affected. Regular cardiovascular exercise has such a positive impact on glycated hemoglobin levels (HbA1C) that it can reduce the need for medication and offer the possibility of remission (if the dietary aspect is also taken into account). The type of cardiovascular activity (intermittent or continuous effort) does not seem to be relevant and provide either way beneficial effects on glycated hemoglobin levels. The American Diabetes Association (ADA) recommends that people with type 2 diabetes perform at least 150 minutes of moderate to high intensity cardiovascular exercise per week. However, this volume remains arbitrary and it is not yet clear what effect cardiovascular exercise volume has on glycated hemoglobin levels in people with type 2 diabetes.

The Study

In an attempt to gain insight, Iranian researchers conducted a meta-analysis of 26 randomized controlled trials involving a total of 1253 people with type 2 diabetes. The selected studies had to last at least 12 weeks (22 studies lasted between 12 and 24 weeks and 4 lasted longer than 24 weeks), report the intensity and duration of the training sessions and assess the impact of training on glycated hemoglobin. Studies that included strength training were excluded.

Of the 26 studies, 13 were conducted exclusively with overweight and obese adults (body mass index >25 kg/m²), with the remaining studies conducted in mixed populations. Five studies were conducted with women, 2 with men, and the rest with both sexes. Finally, most studies (20) recruited physically inactive patients with a sedentary lifestyle.

Results & Analyzes

The main results of this study show that for every 30 minutes of weekly cardiovascular exercise, glycated hemoglobin levels decrease by an average of 0.22%. The greatest decrease (-1.22 to -0.53%) was observed at 140 min/week, regardless of exercise intensity, whereas for studies focusing on moderate to high intensity, the greatest decrease was observed at 120 min/week (-1.26 to -0.68%). However, in both cases, after 100 minutes of weekly cardiovascular activity, a plateau was observed in the decrease of glycated hemoglobin and the differences are no longer significant.

The researchers also observed that a greater reduction in HbA1C was observed in trials that lasted longer than 6 months. However, only 4 studies used a protocol longer than 24 weeks, so it is difficult to draw definitive conclusions. In addition, this reduction was greater in patients without comorbidities associated with type 2 diabetes and in those not using insulin drugs. Those who were overweight or obese were less responsive to the interventions. The researchers observed a reduction in medication use for 13% of patients. And finally, in some trials, 4% of patients experienced hypoglycemia during the sessions.

Practical Applications

Cardiovascular training, whether continuous or intermittent, can significantly lower glycated hemoglobin with important clinical significance. In fact, each 1 percent increase in HbA1C is associated with a 15 to 20 percent greater risk of cardiovascular disease and premature death in type 2 diabetics. Eighty minutes per week is sufficient to reduce the risk of cardiovascular disease by an average of 0.91% (-1.28 - -0.55) with a maximum observed at 120 min/week of -0.98% (-1.26 - -0.68) (for moderate to high intensities).

A progressive and regular practice is therefore particularly important for type 2 diabetics who would like to improve their general health, decrease the risk of long-term problems and cardiovascular complications related to diabetes and reduce the intake of medication. Of course, the combination of an adapted diet will provide even greater overall benefits.


  1. Jayedi A, Emadi A and Shab-Bidar S. Dose-dependent effect of supervised aerobic exercise on HbA1C in patients with type 2 diabetes : A meta-analysis of randomized controlled trials. Sports Med, 2022.

We remind you that you can quote articles by limiting your quotation to 200 words maximum and you must include a nominative link to this one. Any other use, especially copying in full on forum, website or any other content, is strictly prohibited. In doubt, contact us.

Follow us