Mentally retarded individuals--a population at risk?

When comparing the aging process of mentally retarded (MR) persons with the nondisabled population, researchers have established an earlier lower limit for the onset of old age for MR persons and a higher mortality rate. The reason for early senescence has not been successfully resolved, but the finding that cardiovascular disorders are the most prevalent form of disease among elderly MR persons suggests a relationship between lifestyles and higher mortality rate. Indeed, studies that evaluated the cardiovascular fitness (CVF) of MR individuals demonstrated substandard levels of fitness. The results of these studies, however, are not conclusive due to variation in test methodologies, motivational factors, and issues of test validity and reliability. Training studies which have purported to determine trainability of this population have also shown confusing results, perhaps attributed to the same protocol inconsistencies. Therefore, the purposes of this article are 1) to review previous methods of evaluating CVF of MR adults and determine whether testing methodologies invalidate the results of these studies, 2) to review training studies involving adult MR individuals and determine whether this population is capable of improving their CVF, and 3) to identify areas where further research is needed to fully describe the functional cardiovascular characteristics of MR adults.