Habitual Physical Activity, Exercise and Cardiovascular Function in Spinal Cord Injury

Principal Investigator
West, Christopher (ICORD, University of British Columbia)

Mentor
Sheel, William

Network Affiliation
Canadian Vascular Network

 

1. The Health Problem/Issue

Approximately 11,000 individuals in North America sustain a spinal cord injury (SCI) every year. Presently there are over 300,000 people living with SCI in the North America. A SCI is one of the most serious injuries known to humankind. The total annual health cost for Canadians with SCI approaches $3.6 billion. Many of these costs are related to the treatment of secondary complications. Heart disease is the number one cause of illness and death among people with SCI, and people with SCI exhibit risks for heart disease younger and more frequently than the general population. The causes of heart disease are poorly understood at present.
 
A SCI causes a break in the connection between the brain and the spinal cord. The point of the spine at which the SCI occurs determines the degree to which function is affected. If the break occurs high in the spinal cord then it can directly affect the structure and function of the heart and blood vessels. It is possible that altered function of the heart and blood vessels is directly responsible for the high rates of heart disease in people with SCI.
 

2. The Objectives 

The major objectives of this research program are to measure the function of the heart and blood vessels following SCI and to investigate the mechanisms that are responsible for any changes that occur. A second objective is to examine the effect that both physical activity, which describes any bodily movement, and structured exercise have on the health of the heart and blood vessels. In people without SCI we know that maintaining an active lifestyle can improve the health of the heart and blood vessels. For people with SCI the type and amount of physical activity and exercise that they can perform is severely limited, and is usually restricted to exercising the arms only. In the present research program we will investigate whether a new form of exercise that exercises both the arms and the legs of people with SCI is able to improve the health of the heart and blood vessels.
 

3. The Approach

For this research program we will study both humans with SCI and animal models. In the animal models we will make measurements that are unable to be made in humans with SCI, but that are vitally important to improve our understanding of the mechanisms responsible for changes in the function of the heart and blood vessels. Understanding these mechanisms is very important to allow researchers and doctors to devlop new ways to help people with SCI live healthier and happier lives. In humans with SCI, we will fit a device to their wrist which measures how much physical activity they get during a one week period and the locations at which they get the most activity. We will then measure the health of the heart and blood vessels directly in the laboratory. Finally, we will ask 20 people with SCI to complete 8 weeks of exercise training for either the arms alone or the arms and legs combined. We will measure the function of the heart and blood vessels before and after training to see which exercise works best.
 

4. The Unique Factors 

There are two new approaches within the current research program. Firstly, we are able to use some of the same equipment in both animal models and humans with SCI to track changes in the function of the heart and blood vessels. This allows us to take what we find in the animal model and apply it to the human population much easier. The second new approach relates to the type of exercise we are getting people with SCI to perform. Typically people with SCI can only exercise their arms, since their legs are paralysed. Here we will use a specialized piece of cycle equipment where people with SCI have their feet strapped onto pedals. People then actively use their arms to passively turn their legs. This results in a full body exercise that would be otherwise impossible. It is anticipated that by exercising the legs people with SCI can prevent or reverse some of the changes that are known to occur in the leg blood vessels.
 

5. How the project is relevant to the objectives of the initiative 

The proposed research will be the first to try and understand the mechanisms responsible for changes in the heart and blood vessels after SCI. In people without SCI, it is well known that that changes in the function of the heart and blood vessels directly cause heart disease. In people with SCI, we know that heart disease occurs quicker than in people without SCI, and that these individuals are at a much greater risk for stroke. Unfortunately, we do not understand why this is the case and whether or not maintaining and active lifestyle can reduce heart disease. These areas are directly assessed in my proposed research program.
 

6. The Impact

People with SCI consistently report a reduced quality of life compared to people without SCI. Although many different factors are responsible for this reduced quality of life, an inactive lifestyle is known to be one of the biggest contributors. A second factor commonly associated with a reduced quality of life in people with SCI is problems related to cardiovascular health, such as altered blood pressure control along with bowel and bladder problems. A number of studies have now linked an active lifestyle to improved quality if life in people with and without SCI. The current research program will take this research one step further by investigating the factors that determine the reasons why people with SCI do or do not take part in regular physical activity or structured exercise. By understanding these reasons it is anticipated that this research will assist researchers and doctors in getting more people with SCI physically active. This in turn is expected to reduce heart disease and improve quality of life.
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