Repeated Sprints in Fasted State Impair Reaction Time Performance.
The aim of this study was to assess the effects of 3-day Islamic intermittent fasting (3d-IF) on cognitive performance and serum levels of neurotrophic factors (brain-derived neurotrophic factor [BDNF] and vascular endothelial growth factor [VEGF]) before and after repeated sprints.



Twenty-one physically active male Muslims (29.8 ± 5.9 years, exercising 4 ± 1.5 times/week) were randomly assigned to one of 2 experimental sessions: the control or nonfasting session (CS) or the fasting session (FS). These 2 sessions occurred 7 days apart in a counterbalanced crossover design. In both conditions, the test was performed at the same time of day, approximately 1 hour before sunset. In the FS, the test occurred on the third day of the 3d-IF and involved the participants' performance of the following: (a) two series of 5 maximal 5-second sprints and (b) 2 cognitive tasks: One Touch Stockings (OTS) and reaction time (simple and complex RTI).



In both conditions, the participants' reaction times during the RTI test were similar at the pre- and mid-exercise points, but postexercise, simple and complex reaction times were higher in FS compared to CS (p = 0.045, effect size [ES] = 0.21 and p = 0.006, ES = 0.41, respectively). However, OTS performance and serum levels of neurotrophic factors were not influenced by the 3d-IF.



Simple and complex reaction times during the RTI test were negatively affected by the 3d-IF after 2 bouts of intensive repeated sprints.
a Athlete Health and Performance Research Center, Aspetar-Orthopaedic and Sports Medicine Hospital , Doha , Qatar.|b Human Physiology Research Group, Faculty of Physical Education and Physiotherapy Free University of Brussel , Brussels , Belgium.
Anissa
A
Cherif
b Human Physiology Research Group, Faculty of Physical Education and Physiotherapy Free University of Brussel , Brussels , Belgium.|c School of Public Health, Tropical Medicine and Rehabilitation Sciences, James Cook University , Queensland , Australia.
Romain
R
Meeusen
a Athlete Health and Performance Research Center, Aspetar-Orthopaedic and Sports Medicine Hospital , Doha , Qatar.
Abdulaziz
A
Farooq
d Qatar University, College of Arts and Sciences, Sport Science , Doha , Qatar.
Walid
W
Briki
e Laboratory of Physiology , Faculty of Medicine of Sousse, University of Sousse , Sousse , Tunisia.
Mohamed Amine
MA
Fenneni
a Athlete Health and Performance Research Center, Aspetar-Orthopaedic and Sports Medicine Hospital , Doha , Qatar.
Karim
K
Chamari
b Human Physiology Research Group, Faculty of Physical Education and Physiotherapy Free University of Brussel , Brussels , Belgium.|f Fund for Scientific Research Flanders (FWO) , Brussels , Belgium.
Bart
B
Roelands
D000328:Adult; D005215:Fasting; D006801:Humans; D007514:Islam; D008297:Male; D011930:Reaction Time / Q000502:physiology*; D012420:Running
Dietary restriction; anaerobic exercise; brain; cognitive task; memory