Evidence Summary

What is an Evidence Summary?

Key messages from scientific research that's ready to be acted on

Got It, Hide this
  • Rating:

High intensity aerobic exercise lowers blood sugar levels and improves fitness in people with type 2 diabetes

Grace A, Chan E, Giallauria F et al. Clinical outcomes and glycaemic responses to different aerobic exercise training intensities in type II diabetes: A systematic review and meta-analysis Cardiovasc Diabetol. 2017;16:37.

Review question

Do aerobic exercise programs decrease blood sugar levels, increase physical fitness and improve other health outcomes in people with type 2 diabetes? What intensity of aerobic exercise is most effective?


Healthy diet and exercise are known to improve blood sugar levels in type 2 diabetes. Researchers have found that when combined, aerobic (cardio) and resistance (strength training) exercise work well for controlling blood sugar in diabetes. In people without diabetes, high intensity aerobic exercise has been shown to help regulate blood sugar levels and improve physical fitness.

How the review was done

This is a review of 27 randomized-control trials conducted from 1986 to 2014, including a total of 1 372 participants. All the studies were combined in a meta-analysis.

  • All participants were adults with type 2 diabetes.
  • Study participants took part in exercise programs that ranged from four weeks to one year in duration. The exercise sessions varied in intensity and occurred between two to five times per week, with each session being 15 to 75 minutes long, depending on the study.
  • Researchers measured participants’ blood sugar levels (HbA1c), blood insulin levels and insulin resistance (HOMA-IR), a marker of diabetes control. Researchers also measured participants’ physical fitness levels (VO2), as well as lean body mass, body mass index (BMI) and body composition.
  • Results were compared to control groups who did not participate in the exercise programs.

What the researchers found

Aerobic exercise helped to lower blood sugar (HbA1c) and increase fitness levels among participants. Programs that were longer in duration led to greater decreases in blood sugar levels. Compared to low or moderate intensity exercise, high intensity exercise was slightly more effective in decreasing blood sugar and effective in increasing fitness. Insulin resistance, fasting glucose and insulin levels were also improved by the exercise programs.


Aerobic exercise is an effective way to decrease blood sugar levels and improve fitness in people with type 2 diabetes. High intensity aerobic exercise done regularly over longer time periods is most effective.




Control group
A group that receives either no treatment or a standard treatment.
Advanced statistical methods contrasting and combining results from different studies.

Related Web Resources

  • Type 2 diabetes: Screening for adults

    Health Link B.C.
    People at average risk for type 2 diabetes should be tested every 3 years after age 40. You may need to be tested more frequently if you are at higher risk. Find out your risk with the Canadian Diabetes Risk Assessment Questionnaire (link in this resource).
  • High blood sugar can increase cognitive decline

    Berkeley Wellness
    New research shows that if you have high blood sugar, you might be more at risk for cognitive decline as you age. Whether or not you have diabetes, it is important to keep your blood sugar under control.
  • Prediabetes: Which Treatment Should I Use to Prevent Type 2 Diabetes?

    This patient decision aid helps People with prediabetes considering treatment to help prevent type 2 diabetes decide on whether to make a major lifestyle change or take the medicine metformin by comparing the benefits, risks, and side effects of both options.
DISCLAIMER These summaries are provided for informational purposes only. They are not a substitute for advice from your own health care professional. The summaries may be reproduced for not-for-profit educational purposes only. Any other uses must be approved by the McMaster Optimal Aging Portal (info@mcmasteroptimalaging.org).

Register for free access to all Professional content

Want the latest in aging research? Sign up for our email alerts.
© 2012 - 2019 McMaster University | 1280 Main Street West | Hamilton, Ontario L8S4L8 | +1 905-525-9140 | Terms Of Use