Effects of Home-based or Center-based Aerobic Exercise in Patients With Chronic Kidney Disease

The test began with a fixed inclination of 1%. The initial velocity was 2 km/h during the first three minutes with increments of 0.5km/h every minute until the patient reaches physical exhaustion. The ventilatory variables were measured using a gas analyzer. The highest oxygen uptake obtained during the last stage reached was considered the peak oxygen uptake. The ventilatory threshold was determined as the stage preceding the first occurrence of the exponential increase in ventilation, increase in the ventilatory equivalent for oxygen and increase in expired fraction of oxygen. The respiratory compensation point was determined as the stage preceding the second occurrence of the exponential increase in ventilation, increase in the ventilatory equivalent for carbon dioxide and decrease in end-tidal carbon dioxide. Data were analyzed by the average of 20 seconds.

Functional capacity was assessed using a variety of objective measures. These included six-minute walk test (maximal distance walked along an internal corridor during six minutes), two-minute step test (maximal number of steps achieved in stationary walking during two minutes, used to quantifying the aerobic power), sit-to-stand test (maximal sit to stand cycles achieved in 30 seconds, used to quantifying the muscular endurance of the legs), arm curl test (maximal number of arm curl cycles in 30 seconds, used to quantifying the muscular endurance of the arms), sit and reach test (maximal distance achieved in the Wells bench, used to quantifying the general flexibility), back scratch test (maximum amplitude of the arms used to quantifying the arms flexibility) and time up and go test (shorter time to rise from a chair, walk three meters and sit back, used to quantifying the functional mobility).

The Short-Form Health Survey (SF-36) questionnaire was applied to assess the quality of life. The scores for each domain range from 0 to 100%. The higher scores define a better quality of life. The questionnaire was applied individually in a clear and quiet room with the patient rested.

The PSQI assesses the quality of sleep for the last month of the interview. The questionnaire has 19 questions that comprise seven assessment components: quality of sleep, latency, duration, efficiency, nocturnal sleep disturbances, use of sleep medication and daytime sleepiness. Each component receives a score from 0 to 3, in a way that the final score can range between 0 and 21. The higher the score, the worse the quality of sleep, and scores higher than five indicate sleep disturbances.

Blood pressure and resting heart rate were measured before the cardiopulmonary exercise test.