Effects of Fasting During Ramadan Month on Cognitive Function in Muslim Athletes

Changi General Hospital, Singapore.
Asian Journal of Sports Medicine 09/2011; 2(3):145-153. DOI: 10.5812/asjsm.34753
Source: PubMed


Our study aimed to profile the effect of fasting during the Ramadan month on cognitive function in a group of healthy Muslim athletes.
Eighteen male athletes underwent computerized neuropsychological testing during (fasting) and after (non-fasting) Ramadan. Diet was standardized, and tests were performed at 0900h and 1600h to characterize potential time-of-day (TOD) interactions. Psychomotor function (processing speed), vigilance (visual attention), visual learning and memory, working memory (executive function), verbal learning and memory were examined. Capillary glucose, body temperature, urine specific gravity, and sleep volume were also recorded.
Fasting effects were observed for psychomotor function (Cohen's d=1.3, P=0.01) and vigilance (d=0.6, P=0.004), with improved performance at 0900h during fasting; verbal learning and memory was poorer at 1600h (d=-0.8, P=0.03). A TOD effect was present for psychomotor function (d=-0.4, P<0.001), visual learning (d=-0.5, P=0.04), verbal learning and memory (d=-1.3, P=0.001), with poorer performances at 1600h. There was no significant fasting effect on visual learning and working memory.
Our results show that the effect of fasting on cognition is heterogeneous and domain-specific. Performance in functions requiring sustained rapid responses was better in the morning, declining in the late afternoon, whereas performance in non-speed dependent accuracy measures was more resilient.

Download full-text


Available from: Abdul Rashid Aziz
  • Source
    • "Survey. A survey was completed at the conclusion of the CBB assessment to obtain subjective evaluations of the extent to which a number of factors influenced cognitive performance, including those identified in past research (Falleti, Maruff, Collie, Darby, & McStephen, 2003; Lewis et al., 2010; Olver, Pinney, Maruff, & Norman, 2015; Tian et al., 2011). For a list of all questions, see Table 2. Questions 1–10 on the survey required individuals to answer using a five-point Likert scale with descriptors " Extremely, " " Very, " " Moderately, " " Slightly, " and " Not at all. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Repeat cognitive assessment comparing post-injury performance to a pre-injury baseline is common in concussion management. Although post-injury tests are typically administered in clinical settings, baseline tests may be conducted individually with one-on-one supervision, in a group with supervision, or without supervision. The extent to which these different test settings affect cognitive performance is not well understood. To assess if performance on the Cogstate Brief Battery (CBB) differs across these settings, tests completed individually with one-on-one supervision were compared to those taken either in a group with supervision or individually but without supervision. A crossover study design was utilized to account for any effect of individual variability or test order to provide an unbiased examination of the effect of test setting on cognitive performance. Young adult participants completed an individually supervised test either before or after also completing a group or unsupervised test. CBB scores from the same individuals were not significantly different across test settings. Effect sizes ranged in magnitude from .09 to .12 for supervised versus unsupervised tests and from .01 to .37 for individual versus group tests across CBB tasks. These results suggest that cognitive testing with the CBB in alternate settings can provide valid cognitive data comparable to data obtained during individually supervised testing.
    Full-text · Article · May 2015 · The Clinical Neuropsychologist
  • Source
    • "The second study in which a deficit was observed tested individuals during Ramadan fasting (Roky et al., 2000); slow reaction time was seen only on the sixth day of fasting and the authors suggested this slowing may have been better accounted for by fatigue. However, Tian et al. (2011) also tested participants during Ramadan fasting and found that fasted athletes performed better in a choice reaction-time task. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Numerous investigations have been conducted on the impact of short-term fasting on cognition in healthy individuals. Some studies have suggested that fasting is associated with executive function deficits, however findings have been inconsistent. The lack of consensus regarding the impact of short-term fasting in healthy controls has impeded investigation of the impact of starvation or malnutrition in clinical groups, such as anorexia nervosa (AN). One method of disentangling these effects is to examine acute episodes of starvation experimentally. The present review systematically investigated the impact of short-term fasting on cognition. Studies investigating attentional bias to food-related stimuli were excluded so as to focus on general cognition. Ten articles were included in the review. The combined results are equivocal: several studies report no observable differences as a result of fasting and others show specific deficits on tasks designed to test psychomotor speed, executive function, and mental rotation. This inconsistent profile of fasting in healthy individuals demonstrates the complexity of the role of short-term fasting in cognition; the variety of tasks used, composition of the sample, and type and duration of fasting across studies may also have contributed to the inconsistent profile. Additional focused studies on neuropsychological profiles of healthy individuals are warranted in order to better develop an understanding of the role of hunger in cognition.
    Full-text · Article · Feb 2014 · Appetite
  • Source
    • "However, a recent study that assessed cognitive functioning at 0:900 h and 16:00 h in a group of healthy Muslim athletes and controlled for circadian rhythm and meal timing and composition revealed that performance in functions requiring sustained rapid responses was better in the morning and declined in the late afternoon [41]. In fact, performance in the morning was better in the fasting compared to the non-fasting period, which may indicate a decline due to time awake [41]. However, a drawback of this study is the fact that the investigators did not assess sleep duration and quality objectively and did not assess sleep patterns during Ramadan. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Ramadan fasting and its attendant lifestyle changes induce changes in the circadian rhythm and in associated physiological and metabolic functions. Previous studies that have assessed psychomotor performance during Ramadan fasting have reported conflicting results. Therefore, we designed this study to objectively assess the effects of intermittent fasting during and outside Ramadan (to control for lifestyle changes) on drowsiness, blink total duration and mean reaction time (MRT) test while controlling for potential confounders. Eight healthy volunteers with a mean age of 25.3 +/- 2.9 years and a mean body mass index (BMI) of 23.4 +/- 3.2 kg/m2 reported to the sleep laboratory on four occasions for polysomnography (PSG) and drowsiness and psychomotor assessments as follows: 1) adaptation; 2) 4 weeks before Ramadan while performing the Islamic fasting for 1 week (baseline fasting - BLF); 3) 1 week before Ramadan (non-fasting baseline) (BL); and 4) during the second week of Ramadan while fasting (Ramadan). OPTALERTTM was used to objectively assess daytime drowsiness using the Johns Drowsiness Scale (JDS), and blink total duration and a visual reaction time test were used to assess MRT. Rapid eye movement (REM) sleep percentage was significantly lower at BLF (17.7 +/- 8.1%) and at Ramadan (18.6 +/- 10.7%) compared with BL (25.6 +/- 4.8%) (p<0.05). There were no significant differences between JDS scores and blink total duration during the two test periods in BL, BLF and Ramadan. There were no significant changes in MRT during BL, BLF and Ramadan. Under controlled conditions of fixed light/dark exposure, caloric intake, sleep/wake schedule and sleep quality, the Islamic intermittent fasting has no impact on drowsiness and vigilance as measured by the JDS, total blink duration and MRT.
    Full-text · Article · Aug 2013 · Behavioral and Brain Functions
Show more