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Diabetes Metab. 2006 Dec;32(6):617-24.

Effect of Ramadan fasting on fuel oxidation during exercise in trained male rugby players.

Author information

1
Unité de Recherche de l'Institut Supérieur du Sport et de l'Education Physique, Kef, Tunisie. e.bouhlel@wanadoo.tn

Abstract

PURPOSE:

The aim of this study was to assess the effect of Ramadan fasting on substrate oxidation in trained athletes during moderate-intensity exercise.

METHODS:

Nine trained men (age: 19+/-2 yr, Height: 1.78+/-0.74 m) were tested on three occasions: during a control period immediately before Ramadan (C), at the end of the first week (Beg-R), and during the fourth week of Ramadan (End-R). On each occasion, they performed submaximal cycle ergometer exercise, with work-rates that were increased progressively (loadings corresponding to 20, 30, 40, 50, 60% of Wmax). Steady-state substrate oxidation was evaluated by indirect calorimetry.

RESULTS:

Participants showed significant decreases in body mass and body fat at the end of Ramadan, relative to initial control values (P<0.001). The daily food intake was also reduced during Ramadan (P<0.01). Haemoglobin concentrations and hematocrit were significantly higher at the end-Ramadan, both at rest (P<0.001 and P<0.0001 respectively) and after exercise, (P<0.05 and P<0.01 respectively) compared to control measurements made before Ramadan. At the end of Ramadan, our subjects had increased their fat utilization during exercise. The cross-over was observed at a higher intensity at the End-R (35% vs. 30% of Wmax, P<0.001). For the same power output, the Lipox max was also higher at the End-R, compared to control value (265+/-38 vs. 199.1+/-20 mg/min, P<0.001).

CONCLUSION:

Ramadan fasting increases the lipid oxidation of trained athletes during submaximal exercise. The increased fat utilisation may be related to decreases in body mass and body fat content.

PMID:
17296516
DOI:
10.1016/S1262-3636(07)70317-8
[Indexed for MEDLINE]

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