title: Validity of Ratings of Perceived Exertion in Patients with Type 2 Diabetes.
abstract: OBJECTIVE
  To examine whether a subjective measure of moderate-intensity exercise (12-13 on Borg's ratings of perceived exertion scale; RPE) corresponds to the target heart rate for moderate-intensity exercise (40-59% heart rate reserve; %HRR) and to determine the characteristics of those for whom RPE does not appropriately estimate exercise intensity.
  
  
  METHODS
  3582 individuals with type 2 diabetes (age: 58.3±6.8 years; BMI: 35.9±5.9 kg/m2) underwent a maximal exercise test and minute-by-minute HR and RPE were recorded. Linear regression was used to determine the %HRR corresponding to an RPE of 12 and 13 for each individual.
  
  
  RESULTS
  At an RPE of 12 or 13, 57% of participants fell within the target 40-59%HRR range, while 37% and 6% fell above and below this range, respectively. Participants with a %HRR ≥60% (above range) were more likely to be female (OR: 1.19; 95% CI: 1.01,1.40), African American (OR: 1.65; 95% CI: 1.35, 2.02) or Hispanic (OR: 1.57; 95% CI: 1.27, 1.95), have a higher BMI (OR: 1.03; 95% CI 1.01, 1.04) and HRmax(OR: 1.02; 95% CI: 1.01, 1.02), and lower fitness (OR: 0.90; 95% CI: 0.85, 0.94) and RPEmax(OR: 0.68; 95% CI: 0.63, 0.73), compared to those within the target 40-59%HRR range (p-values'<0.05).
  
  
  CONCLUSIONS
  RPE appropriately gauges exercise intensity in approximately half of overweight individuals with type 2 diabetes; however, more than one-third of participants were at an increased risk of exercising at a higher than prescribed intensity when using RPE. Future studies should continue to examine the characteristics of individuals for whom RPE appropriately estimates exercise intensity and for those whom it does not.
authors.affiliation: Weight Control and Diabetes Research Center, The Miriam Hospital and Brown Medical School, Providence, RI.
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Unick
authors.affiliation: Wake Forest University School of Medicine, Winston-Salem, NC.
authors.forename: Sarah
authors.initials: S
authors.lastname: Gaussoin
authors.affiliation: Universitiy of Minnesota, Minneapolis, MN.
authors.forename: Judy
authors.initials: J
authors.lastname: Bahnson
authors.affiliation: Phoenix Epidemiology and Clinical Research Branch, NIDDK, NIH, Phoenix, AZ.
authors.forename: Richard
authors.initials: R
authors.lastname: Crow
authors.affiliation: Northern Navajo Medical Center, Shiprock, NM.
authors.forename: Jeff
authors.initials: J
authors.lastname: Curtis
authors.affiliation: Center for Women's Health Research, Divisions of General Internal Medicine and Cardiology, Department of Medicine, University of Colorado School of Medicine, Aurora, CO.
authors.forename: Tina
authors.initials: T
authors.lastname: Killean
authors.affiliation: Johns Hopkins University, Baltimore, MD.
authors.forename: Judith G
authors.initials: JG
authors.lastname: Regensteiner
authors.affiliation: Department of Health and Physical Activity, Physical Activity and Weight Management Research Center, University of Pittsburgh, Pittsburgh, PA.
authors.forename: Kerry J
authors.initials: KJ
authors.lastname: Stewart
authors.forename: Rena R
authors.initials: RR
authors.lastname: Wing
authors.forename: John M
authors.initials: JM
authors.lastname: Jakicic
keywords: diabetes; exercise; exercise prescription; obesity; ratings of perceived exertion; type 2 diabetes