Perceived exertion with glucose ingestion in adolescent males with IDDM.

Abstract

PURPOSE:
The rating of perceived exertion (RPE) is an indicator of exercise effort in adolescents that may be influenced by certain pediatric conditions. The purpose of this study was to determine the influence of insulin-dependent diabetes mellitus (IDDM) and glucose intake on RPE.

METHODS:
Eight male adolescents with IDDM and eight healthy controls of similar age, weight, and VO_2max cycled for 60 min at 60%VO_2peak on two occasions spaced 1-4 wk apart. During a control trial (CT), subjects drank water, and in a glucose trial (GT), glucose at a rate of ~ 1.5 gkg^-1h^-1. Heart rate, ventilation, and RPE (Borg 6-20 scale) were assessed at 5, 25, 35, and 55 min and blood glucose and lactate levels before and at 30 and 60 min.

RESULTS:
RPE in both trials was 15-25% higher in IDDM versus healthy subjects (F = 8.83; df = 1.14; eta-squared = 0.39; P = 0.01). In CT, it increased from 10.6 ± 0.4 at 5 min to 15.2 ± 0.6 at 55 min in IDDM and from 9.3 ± 0.9 at 5 min to 13.0 ± 0.8 at 55 min in healthy adolescents. In GT, RPE increased similarly to CT in the IDDM group but was 1-2 points lower in the healthy group. Blood glucose levels were 4.8 ± 1.8 mmolL^-1 higher by the end of exercise in GT than in CT for the IDDM and healthy groups, respectively. There were no differences in heart rate, ventilation, or lactate levels between the groups or trials.

CONCLUSIONS:
For exercise performed at a similar moderate intensity, RPE in IDDM is higher by 2-3 points than in controls. Compared with water, glucose intake is associated with lower RPE in healthy, but not in IDDM, adolescents.