Perceptual and Motor Skills, 2010, 111, 2, 365-378. © Perceptual and Motor Skills 2010 DOI 10.2466/06.13.15.27.PMS.111.5.365-378 ISSN 0031-5125 LACTATE THRESHOLD PREDICTION BY BLOOD GLUCOSE AND RATING OF PERCEIVED EXERTION IN PEOPLE WITH TYPE 2 DIABETES 1, 2 HERBERT GUSTAVO SIMÕES, WOLYSSON CARVALHO HIYANE, RONALDO ESCH BENFORD, BIBIANO MADRID, AND FRANCISCO ANDRIOTTI PRADA Catholic University of Brasília–UCB SÉRGIO RODRIGUES MOREIRA Federal University of Vale do São Francisco (UNIVASF), PE RICARDO JACÓ DE OLIVEIRA University of Brasília–UnB FÁBIO YUZO NAKAMURA State University of Londrina–UEL CARMEN SÍLVIA GRUBERT CAMPBELL Catholic University of Brasília–UCB Summary.—The validity of rating of perceived exertion (RPE) in predicting lactate threshold during an incremental test was analyzed in 15 men with type 2 diabetes (M age = 53.4 yr., SD = 12.9). Blood glucose, lactate, and minute ventila- tion (VE)/VO 2 responses identiied the lactate, ventilatory, and glucose thresholds. Workloads (W) corresponding to RPEs 12, 13, 14, and 15 were determined. Second- order polynomials it to VE/W and [lac]/W ratios corresponding to RPEs of 9–10, 12–13, and 16–17 also identiied workloads above which there was an overpropor- tional increase in VE and [lac]. These workload breakpoints did not difer, although at RPE 12 underestimated and at RPE 15 overestimated lactate threshold. RPE 13 and 14 and the responses of VE/W and [lac]/W to submaximal exercise accurately predicted lactate threshold. It has been shown that during an incremental exercise test, blood glu- cose concentration decreases until lactate threshold is atained, increas- ing thereater (Simões, Campbell, Kokubun, Denadai, & Baldissera, 1999). This increase in blood glucose concentration ater reaching the lactate threshold was atributed to higher sympathetic activity which leads to a greater rate of glycogenolysis in the liver. Therefore, the exercise intensity (i.e., workload in Wats, speed in km/hr.) at which the blood glucose con- centration begins to increase during the incremental test is called the in- dividual glucose threshold and has been observed in young healthy subjects during running (Sotero, Pardono, Landwehr, Campbell, & Simões, 2009), 1 Address correspondence to Prof. Herbert Gustavo Simões, Ph.D., QS07, LT1 s/n. Bloco G Sala 116, CEP 72030-170 Águas Claras, Brasília, DF-Brazil or e-mail (hgsimoes@gmail.com). 2 Grant support was obtained from Conselho Nacional de Desenvolvimento Cientíico e Tecnológic-CNPq (proc. 475575/2004-0), Fundação de Apoio à Pesquisa do Distrito Fede- ral–FAP-DF, and from Sistema de Gestão de Pesquisa (SIGEP/UCB). The authors are grateful to CNPq and FAP-DF for inancial support and to Laboratório de Avaliação Física e Trein- amento (LAFIT-UCB) and Micromed-DF for technical assistance.