Exercise as it relates to Disease/The Effects of Aerobic Exercise on Patients with Gastrointestinal Symptoms

Note this analysis refers to the journal article by Robinson et al. (1998) entitled Effect of a Low-Impact Exercise Program on Bone Mineral Density in Crohn's Disease: A Randomized Controlled Trial.

Background Information
The World Gastroenterology Organization defines inflammatory bowel disease (IBD) as "a group of idiopathic chronic inflammatory intestinal conditions". One of the main disease categories of IBD is Crohn's Disease (CD) which is a chronic disease that causes inflammation and irritation of the digestive tract. Symptoms of CD include inflammation, intestinal obstruction and malnutrition; Crohn's Disease of the large intestine has also been seen to increase the risk of colon cancer.

Prevalence
Crohn's Disease is reported to affect 155 per 100, 000 people living in the Australasian area and appears to be more prevalent in urban areas. CD is most likely to develop in people between the ages of 20 and 29, with factors such as cigarette smoking and a family history of IBD also seen to increase the likelihood of Crohn's Disease. Incidence rates appear to decrease between the ages of 30-60 with an increase in prevalence from the seventh decade of life.

Crohn's Disease, Osteoporosis and Exercise
Crohn's Disease has been seen to be a potential risk factor for low bone mineral density and the development of osteoporosis. Low bone mineral density in CD patients has been associated with an increased risk of fractures. Physical activity has been seen to increase bone mineral density in young adults, as well as slowing the rate of bone loss in later life.

Where is the research from?
This study was headed by Richard Robinson from the Gastrointestinal Research Unit of the Leicester General Hospital, with grant support from the National Association for Colitis and Crohn's Disease. Research was conducted within the Leicester-shire and the findings were published by the American Gastroenterological Association.

What kind of research was this?
This research was conducted as a randomized controlled study where stratified block randomization was used to ensure both the intervention and control groups contained individuals with similar age, gender, and postmenopausal status.

What did the research involve?
The purpose of this study was to discover the effects of a one year low-impact exercise program on the bone mineral density of patients with Crohn's Disease. An exclusion protocol was used to narrow the target group to 120 eligible patients.

Characteristics that were measured before the intervention include: After randomization, 57 enrolled respondents were placed in the control group, 60 in the exercise group and the remaining three individuals were excluded due to having factors featured in the exclusion protocol. The mean age across the study was 40 years with 59% of the total group being female. Bone mineral density (g/cm2) of all participants were measured by a single investigator at baseline and 12 months at the hip and spine (L2-L4) using dual energy x-ray absorptiometry. Each exercise session consisted of a five minute whole body warm-up, 12 core floor-based exercises, and a five minute pulse-lowering stretching period. Full compliance was considered if subjects participated in at least two sessions a week and a minimum of 10 sessions each month.
 * Current steroid use;
 * Duration of disease;
 * Disease activity;
 * Body Mass Index;
 * Dietary calcium intake; and,
 * Total energy.

What were the basic results?
The main results of Robinson's study include the following:
 * 1) Patients who participated in the training group achieved an increased bone mineral density across all measured sites;
 * 2) A positive association between increased bone mineral density at the hip & spine and the number of exercise sessions completed; and,
 * 3) Patients involved in the training program reported no serious adverse effects due to exercise.

What conclusions can we take from this research?
Vigorous aerobic exercise such as endurance running and cycling can have a detrimental effects on the gastrointestinal system as blood flow is shifted away from these organs towards the lungs and active muscles. Blood flow away from the gastrointestinal system leads to changes in motility, absorption and secretion causing hazards such as nausea, diarrhoea, heartburn, and gastrointestinal bleeding. Robinson's study was able to show that a low-impact exercise intervention had no serious effects on disease activity. However, a limitation to Robinson's study is that a relatively poor exercise compliance caused the results to fail to produce a significant difference between the exercise group and control group. A further limitation is that this study was conducted 18 years ago, but more recent studies have suggested that although exercise can cause acute gastrointestinal symptoms, maintained physical activity can produce a protective effect and reduce the risk of colon cancer.

Practical Advice
Although there are limitations with Robinson's study, full compliance to exercise can improve bone mineral density in patients with Crohn's Disease as the increased load causes a strain to be placed on the bone resulting in an increase in strength and density. High-impact physical activity such as jumping exercises seem to have a greater effect as the larger strain on the axial skeleton causes a greater adaptation. Patients who are unable to participate in high-impact exercise should complete a low-impact program as light-aerobic physical activity such as walking seem to improve quality of life without causing an increase in disease activity.

Information on Crohn's Disease
Centre for Digestive Diseases

Website: http://www.cdd.com.au/index.html

Gastroenterological Society of Australia

Website: http://www.gesa.org.au/index.asp

Further Reading on Exercise and Crohn's Disease
Benefits and Hazards of Physical Activity on the Gastrointestinal System

Website: http://gut.bmj.com/content/48/3/435.full.pdf+html

Digestion, Absorption and Exercise

Website: http://www.ncbi.nlm.nih.gov/pubmed/8460288