Impact of high- and low-intensity targeted exercise training on the type of substrate utilization in obese boys submitted to a hypocaloric diet.
BACKGROUND
We assessed the effect of two programs combining a hypocaloric diet with low-intensity (LI) or high-intensity (HI) exercise training, during two months, on substrate utilization at exercise in obese children.


METHODS
Fifteen obese boys participated in a combined program of exercise and caloric restriction-induced weight loss (diet starting two weeks before the training program). The maximal fat oxidation point (Lipox max) was determined to individualize exercise training. Training consisted of cycling at either LI (Lipox max) for seven children or HI (Lipoxmax+40% Lipox max) for eight children.


RESULTS
All children exhibited a decrease in weight (LI: -5.2 kg +/- 0.7 (P<0.01), HI: -7 kg +/- 0.7 (P<0.01)). While in the LI group, both fat and CHO oxidation were unchanged after training, HI group oxidize less fat and more CHO after training when exercising at 20% and 30% Wmax th (P = 0.02).


CONCLUSIONS
While a LI exercise training program maintains (but does not improve) the ability to oxidize fat at exercise, HI training actually shifts towards CHO the balance of substrate oxidation during exercise. Thus, a low intensity training protocol seems to counteract to some extent the decline in lipid oxidation at exercise that occurs after a hypocaloric diet, and is thus likely to be synergistic to diet in the weight lowering strategy.
Brandou
F
F
Service central de physiologie Clinique, Unité CERAMM (Centre d'Exploration et de Réadaptation des Anomalies Métaboliques et Musculaires), CHU Lapeyronie, 34295 Montpellier Cedex 5, France. fredbrandou@yahoo.fr
Savy-Pacaux
A M
AM
Marie
J
J
Bauloz
M
M
Maret-Fleuret
I
I
Borrocoso
S
S
Mercier
J
J
Brun
J F
JF
D000273:Adipose Tissue / Q000033:anatomy & histology; D000293:Adolescent; D000704:Analysis of Variance; D001642:Bicycling / Q000502:physiology*; D015992:Body Mass Index; D002245:Carbon Dioxide / Q000032:analysis; D002648:Child; D003131:Combined Modality Therapy; D004038:Diet, Reducing; D004040:Dietary Carbohydrates; D005081:Exercise Therapy / Q000379:methods*; D006801:Humans; D008297:Male; D009765:Obesity / Q000628:therapy*; D010101:Oxygen Consumption; D015431:Weight Loss
D004040:Dietary Carbohydrates; D002245:Carbon Dioxide