Endurance activities may lead to major health benefits for people with diabetes

Exercise can mitigate damage caused by disease. Faculty of Kinesiology researcher Dr. David Montero, PhD, is studying the relationship of blood volume, cardiac dysfunction and impaired exercise capacity on those who have Type 1 and Type 2 diabetes, and his research is published in the high-impact journal The Lancet Diabetes & Endocrinology.

Diabetes affects more than 400 million people worldwide and those with this condition have weak cardiac function and a very high risk of heart disease and stroke.

Endurance exercise is key to blood volume

Blood volume, the amount of fluid in the circulation, is a key component of the cardiovascular system, and determines the capacity to perform aerobic activities. According to Montero’s paper, blood volume is low in patients with diabetes irrespective of gender, age and activity level.

“Current research emphasizes the importance of training the musculoskeletal system to keep those with diabetes healthy," says Montero. "However, endurance rather than strength exercise training is the main strategy that may help these individuals to increase blood volume and aerobic capacity, plausibly entailing major health benefits.”

Montero is lead author of the paper, which systematically reviews the literature delving into the potential mechanistic role of low blood volume in cardiac dysfunction and reduced aerobic capacity. Aerobic capacity refers to the amount of oxygen consumed during maximum effort during exercise.

Endurance exercises include activities such as cycling, running or rowing for prolonged periods. Previous works from Montero demonstrate that endurance training is the most effective intervention to improve blood volume and aerobic capacity in healthy individuals.

Many factors at play

“Still, even with endurance training, these gains may not translate to all diabetes patients because of a variety of factors, including the use of specific drugs and/or the impairment of mechanisms regulating blood volume, including kidney sensitivity to certain hormones, protein loss from the circulation and baroreflex dysfunction,” says Montero. He has a joint appointment in the Department of Cardiac Sciences at the Cumming School of Medicine. Baroreflex dysfunction occurs when the ability to control changes in blood pressure and heart rate is partially lost.

“Once we discover what limits blood volume expansion in this population, we might find a way for those with Type 1 and Type 2 diabetes to fully benefit from endurance training,” he adds.

Montero says future studies on diabetes patients will clarify the mechanisms of low blood volume and its interplay with cardiac function and aerobic capacity. 

The paper, "The Role of Blood Volume in Cardiac Dysfunction and Reduced Exercise Tolerance in Patients with Diabetes Mellitus," was published in The Lancet Diabetes & Endocrinology and written by Dr. David Montero, PhD (Faculty of Kinesiology, Cumming School of Medicine, and a member of the Libin Cardiovascular Institute of Alberta, University of Calgary); Dr. Candela Diaz-Canestro, PhD (Faculty of Kinesiology, Libin Cardiovascular Institute of Alberta, University of Calgary); Laura Oberholzer, MSc (Department of Clinical Medicine, Rigshospitalet, University of Copenhagen, Denmark); Dr. Carsten Lundby, PhD (Inland Norway University of Applied Sciences, Lillehammer, Norway).