Good cardiovascular endurance allows an individual to have high energy levels throughout the day and lowers the chance for developing Type II diabetes, heart disease, stroke, and hypertension. It is important to note that most of the research on the fitness levels of people with mental retardation is for individuals with mild or moderate mental retardation. There is very little research on people with severe mental retardation. Several studies have shown that the fitness levels of people with mental retardation are significantly lower than the general population. Most people with mental retardation lead an inactive lifestyle, and are, therefore, more likely to develop hypokinetic diseases.
Some experts consider physical inactivity a major health risk among people with mental retardation.
Most people with mental retardation have much lower strength levels than the general population, which may limit their employment opportunities in work settings that require a high level of muscular fitness. A low level of muscle strength and endurance also makes it difficult to perform activities such as lifting or carrying objects or walking up a flight of stairs. Cardiovascular endurance is considered by most exercise experts to be the most important indicator of fitness. The majority of researchers who have tested the cardiovascular fitness levels of people with mental retardation have reported fitness levels similar to those of the most inactive people in the general population. In one study it was shown that the cardiovascular endurance of adults with mental retardation was as low as people with heart problems.