Int J Sports Med 2008; 29(9): 706-712
DOI: 10.1055/s-2007-989454
Physiology & Biochemistry

© Georg Thieme Verlag KG Stuttgart · New York

Prediction of Glucose Oxidation Rate during Exercise

M. P. Francescato1 , M. Zanier1 , F. Gaggioli1
  • 1Department of Biomedical Sciences and Technologies, University of Udine, Udine, Italy
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Publikationsverlauf

accepted after revision December 5, 2007

Publikationsdatum:
22. Januar 2008 (online)

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Abstract

Recently, the relationship between percentage maximal heart rate vs. glucose oxidation rate has been proposed as a tool for estimating glucose oxidation rate during exercise in insulin-dependent diabetic patients. The reliability of this relationship and its applicability to long-term exercise is evaluated. Eight healthy volunteers performed a graded cycloergometric exercise (10-min steps at 30, 50, 70, 90 % of ventilatory threshold). Heart rate and glucose oxidation rate (by indirect calorimetry) were measured during the last 5 min of each step. Volunteers underwent then three 1-hour constant intensity rides at 40, 60, 80 % of ventilatory threshold. Heart rate was recorded continuously; glucose oxidation rate was determined over 15-min periods. The percentage maximal heart rate vs. glucose oxidation rate relationship obtained from the graded exercise matched that previously reported. Independently of intensity, glucose oxidation rates observed during the 1-hr rides were linearly related to the estimated ones (R2 > 0.96, p < 0.001), being, however, progressively over-estimated in subsequent exercise periods. The proposed correction yields values close to the identity line (y = 1.001 · x; R2 = 0.974, p < 0.001), the difference between observed and “corrected” values amounting to 0.23 ± 2.17 mg · min−1 · kg−1. In conclusion, glucose oxidation rate can be estimated from heart rate, once proper correction factors are applied for long duration exercises.

References

Dr., MD Maria Pia Francescato

University of Udine
Department of Biomedical Sciences and Technologies

p.le M. Kolbe 4

33100 Udine

Italy

Telefon: + 39 04 32 49 43 36

Fax: + 39 04 32 49 43 01

eMail: MFrancescato@mail.dstb.uniud.it