Reliability of perceived exertion during graded exercise testing in apparently healthy adults.

PURPOSE: Ratings of perceived exertion (RPE) are widely used for monitoring individuals during graded exercise testing. Studies of the reliability of RPEs across various exercise conditions have produced mixed results. The purpose of this study was to assess the reliability of RPEs during graded exercise testing by comparing the perceptual-physiological relationship between the Bruce and Balke treadmill protocols throughout a broad range of relative exercise intensities. METHODS: Thirty-eight middle-aged men and women completed two maximal treadmill graded exercise testing separated by 48 hours. Test order was randomly assigned. RPEs were compared across protocols and between gender at selected exercise intensities using a series of two-way analysis of variances with repeated measures. RESULTS: A comparison of RPEs (Borg 15-point scale) during the graded exercise testing revealed significant protocol and gender differences at 40%, 60% and 80% of maximal heart rate reserve. RPEs were significantly higher during the Balke protocol compared to the Bruce at each intensity (45% = 9.5 +/- 2.0 vs. 8.3 +/- 1.6; 60% = 12.7 +/- 2.4 vs. 11.1 +/- 2.3; 80% = 15.7 +/- 2.2 vs. 14.1 +/- 2.0). In addition, men rated each intensity significantly higher than the women (P < 0.05). CONCLUSIONS: The results from the present study confirm that the perceptual-physiological relationship observed during graded exercise testing varies as a function of the treadmill protocol employed and that these differences extend throughout the exercise training intensity range (40--80% of maximal heart rate reserve) recommended for healthy adults. The perceptual differences between the protocols could not be accounted for by any of the physiological measures assessed within the study. These results have implications when using RPEs from exercise testing for exercise prescription purposes.

A review of heart rate and blood pressure responses in the cold in healthy subjects and coronary artery disease patients.

Despite methodological differences in the limited number of studies reviewed, it appears that cardiovascular responses at rest and during exercise in the cold differ between patients with CAD and healthy subjects (Figures 1 and 2). This difference remains, even when attempting to control for investigation time and conditions. Typical exercise time reported for patients with CAD exercising in the cold is 4 to 8 minutes, where HR and SBP are generally the same or higher. Data corresponding to a similar time frame (5-15 minutes) in healthy subjects show HR to be lower or no different, whereas SBP was similar in both studies. Logically, healthy subject's RPP values would be similar or lower in the cold, which may be a teleological development to conserve myocardial oxygen uptake in the face of elevated sympathetic stimulation during cold exposure. The lower HR would offset the cold-induced hypertension and also help to preserve cardiac output. In healthy subjects, cardiac output is similar in the cold despite a higher stroke volume (SV) due to the lower HR. However, the similar cardiac output reported by Epstein and colleagues in patients with CAD, both at rest and during exercise at 15 degrees C, was obtained by increases in SV and HR. A blunted peripheral vasoconstriction response in older subjects could lead to reduced central blood volume with a corresponding decrease in venous return and SV. An inability to maintain an appropriate SV in the cold by patients with CAD may be responsible for the elevated HR to maintain cardiac output. However, in healthy subjects, SV appears to have a triphasic response.(ABSTRACT TRUNCATED AT 250 WORDS)