Original Research

Effects of Ramadan Intermittent Fasting on Middle-Distance Running Performance in Well-Trained Runners

Brisswalter, Jeanick PhD^*; Bouhlel, Ezzedine PhD^†; Falola, Jean Marie PhD^‡; Abbiss, Christopher R PhD^§; Vallier, Jean Marc MD, PhD^¶; Hauswirth, Christophe PhD^‖

Author Information

From the *Laboratory of Human Motricity, Education Sport and Health, University of Nice Sophia Antipolis, Nice, France; †Medicine Faculty, Laboratory of Physiology, University of Sousse, Sousse, Tunisia; ‡University of d'Abomey-Calavi, Porto Novo, Benin; §School of Exercise, Biomedical and Health Sciences, Edith Cowan University, Joondalup, Australia; ¶Laboratory of Human Motricity, Education Sport and Health, University of South France Toulon Var, Toulon, France; and ‖National Institute of Sport Expertise and Performance, Paris, France.

Submitted for publication October 29, 2010; accepted June 14, 2011.

The authors report no conflicts of interest.

Corresponding Author: Jeanick Brisswalter, PhD, Laboratory of Human Motricity, Education Sport and Health, University of Nice Sophia Antipolis, BP 3259, Nice 06205, France ([email protected]).

Clinical Journal of Sport Medicine 21(5):p 422-427, September 2011. | DOI: 10.1097/JSM.0b013e3182293891

Abstract

Objective:

To assess whether Ramadan intermittent fasting (RIF) affects 5000-m running performance and physiological parameters classically associated with middle-distance performance.

Design:

Two experimental groups (Ramadan fasting, n = 9, vs control, n = 9) participated in 2 experimental sessions, one before RIF and the other at the last week of fasting.

Setting:

For each session, subjects completed 4 tests in the same order: a maximal running test, a maximal voluntary contraction (MVC) of knee extensor, 2 rectangular submaximal exercises on treadmill for 6 minutes at an intensity corresponding to the first ventilatory threshold (VT₁), and a running performance test (5000 m).

Participants:

Eighteen, well-trained, middle-distance runners.

Main Outcome Measures:

Maximal oxygen consumption, MVC, running performance, running efficiency, submaximal V̇O₂ kinetics parameters (V̇O₂, V̇O₂b, time constant τ, and amplitude A1) and anthropometric parameters were recorded or calculated.

Results:

At the end of Ramadan fasting, a decrease in MVC was observed (−3.2%; P < 0.00001; η², 0.80), associated with an increase in the time constant of oxygen kinetics (+51%; P < 0.00007; η², 0.72) and a decrease in performance (−5%; P < 0.0007; η², 0.51). No effect was observed on running efficiency or maximal aerobic power.

Conclusions:

These results suggest that Ramadan changes in muscular performance and oxygen kinetics could affect performance during middle-distance events and need to be considered to choose training protocols during RIF.