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JOURNAL
OF
SPORTS SCIENCE &
MEDICINE
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Research
article
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PEAK FAT OXIDATION RATE DURING WALKING IN SEDENTARY OVERWEIGHT MEN AND WOMEN |
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Gregory C. Bogdanis  ,
Anna Vangelakoudi and Maria Maridaki |
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Department of Sports Medicine & Biology of Physical Activity, University of Athens, Greece |
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© Journal of Sports Science and Medicine (2008) 7, 525 - 531 Search Google Scholar for Citing Articles |
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| ABSTRACT | |||
| The aim of this study was to determine the relative exercise intensity
that elicits maximal fat oxidation during walking in inactive and overweight
men and women and evaluate any possible sex differences. Forty six healthy,
sedentary, overweight men (age: 36.3 ± 1.3 years, body fat: 28.8 ± 0.8%,
n = 28, mean ± SE) and women (age: 36.6 ± 1.8 years, body fat: 37.1 ± 0.8%,
n = 18) participated in the study. Fat oxidation was calculated from expired
air analysis using indirect calorimetry during an incremental treadmill
walking test. Peak fat oxidation rate (PFO) was higher in men compared to
women (0.31 ± 0.02 vs. 0.20 ± 0.02 g.min-1; p < 0.001), but
this difference disappeared when PFO was scaled per kg fat-free mass (4.
36 ± 0.23 vs. 3.99 ± 0.37 mg.kg fat free mass-1.min-1). Also,
the relative exercise intensity at which PFO occurred was similar for men
and women and corresponded to 40.1 ± 1.8 and 39. 5 ± 2.3% of maximal oxygen
uptake (VO2max) and 60.0 ± 1.4 and 57.8 ± 1.4% of maximal heart
rate, respectively. The walking speed corresponding to PFO was 5.5 ± 0.2
and 5.0 ± 0.1 km·h-1 for men and women, respectively. Regression analysis
showed that sex, FFM and VO2max were significant predictors of
PFO expressed in g.min-1 (adjusted R2 = 0.48, p = 0.01). However
when PFO was scaled per kg FFM, only a small part of the variance was explained
by VO2max (adjusted R2 = 0.12, p < 0.05). In conclusion, peak
fat oxidation rate and the corresponding relative exercise intensity were
similar in male and female overweight and sedentary individuals, but lower
compared to those reported for leaner and/or physically active persons.
Walking at a moderate speed (5.0-5.5 km·h-1) may be used as a convenient
way to exercise at an intensity eliciting peak fat oxidation in overweight
individuals.
Key words: Exercise intensity, calorimetry, substrate utilisation. |
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