Use of Heart Rate Reserve and Rating of Perceived Exertion to Prescribe Exercise Intensity in Diabetic Autonomic Neuropathy
OBJECTIVE—Individuals with diabetic autonomic neuropathy (DAN) exhibit an increased resting heart rate but depressed maximal heart rate. Thus, the purpose of this study was to examine the validity of using either percent of heart rate reserve (HRR) or a rating of perceived exertion (RPE) scale to prescribe exercise intensity in diabetic individuals both with and without DAN.
RESEARCH DESIGN AND METHODS—The subjects consisted of 23 individuals with type 2 diabetes, ages 45–75 years, with (DAN; n = 13) or without (No DAN; n = 10) clinical signs of DAN, as assessed by heart rate variability using the expiration-to-inspiration ratio of the R-R interval. Peak aerobic capacity was determined using a graded protocol on a cycle ergometer, with RPE, heart rate, and Vo2 values recorded at each stage.
RESULTS—The subjects were similar with the exception of depressed autonomic function in DAN subjects. Peak respiratory exchange ratio values were significantly higher (P < 0.05) in the DAN group (1.08 ± 0.02 vs. 1.02 ± 0.01 in No DAN subjects), although DAN subjects exhibited a significantly lower (P < 0.05) peak exercise heart rate. A similarly highly linear relationship between %HRR and percent Vo2 reserve (Vo2R) existed for both groups (r = 0.98). A similar slightly weaker relationship (r = 0.94) was found between RPE and %Vo2R.
CONCLUSIONS—In conclusion, in diabetic individuals, %HRR provides an accurate prediction of %Vo2R and can be used to prescribe and monitor exercise intensity, regardless of the presence of DAN. The RPE scale is also a valid, albeit slightly less accurate, method to monitor exercise intensity in diabetic individuals.
- DAN, diabetic autonomic neuropathy
- E:I ratio, inspiration-to-expiration ratio of the R-R interval
- HRR, heart rate reserve
- RER, respiratory exchange ratio
- RPE, rating of perceived exertion
- SEE, standard error of the estimate
- Vo2peak, peak aerobic capacity
- Vo2R, Vo2 reserve
Address correspondence and reprint requests to Sheri R. Colberg, ESPER Department, Old Dominion University, Norfolk, VA 23529. E-mail:.
Received for publication 28 May 2002 and accepted in revised form 13 December 2002.
A.I.V. has acted as a consultant and/or speaker for Pfizer, Genetech, Merck, Eli Lilly, Athena, Bristol-Myers Squibb, Knoll Pharmaceuticals, GlaxoSmithKline, Boston Medical Technologies, Neurometrix, Guilford Pharmaceuticals, R.W. Johnson, Takeda, TEVA Pharmaceutical Industries, and Astrazeneca and has received grant support from GMP-Endotherapeutics, the American Diabetes Association, Housing and Urban Development, NASA, Eli Lilly, Parke-Davis, Astamedica, GlaxoSmithKline, the National Institute of Aging, and R.W. Johnson.
A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.
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