Accelerometry-based physical activity and exercise capacity in pediatric kidney transplant patients

Low physical activity (PA) is increasingly recognized as a risk factor for children with chronic conditions. A few published studies have measured the exercise capacity of solid organ transplant patients; however, no studies have examined the PA intensity of pediatric kidney transplant patients (PTx) using accelerometry. Therefore, our objective was to complement a gold standard exercise capacity protocol with an objective measure to quantify PA intensity levels of PTx. Sixteen PTx (nine girls), 4.9 +/- 2.9 years posttransplant, mean age 13.1 +/- 4.0 years, participated. Mean diethylenetriamine pentaacetic acid glomerular filtration rate (DTPA GFR) = 76.7 +/- 18.0 ml/min/1.73 m(2). Laboratory data included assessment of cardiopulmonary functioning [peak oxygen uptake (VO2peak)] from cycle ergometry and body composition [dual-energy X-ray absorptiometry (DEXA)]. PA was quantified by triaxial accelerometry (3 days). Field testing (FITNESSGRAM) included progressive aerobic cardiovascular endurance run (PACER), curlups, and sit/reach tests. Sex- and age-based criterion standards were used as reference. Below normative values for VO2peak was found in eight children (mean = 27.4 +/- 3.3). Accelerometry data identified only three children who fulfilled daily recommended moderate-vigorous PA level; 58.5% of their time was spent in sedentary activity. Accelerometry data highlights that not only are PTx patients inactive, the activity they do perform is overall of low intensity. PTx also show compromised exercise capacity and physical fitness. Our results suggest the need to assess PA barriers among PTx. Further research is needed to determine appropriate PA recommendations for children posttransplant.