Rachida Roky | PubMed Health

PubMed2004

Physiological and chronobiological changes during Ramadan intermittent fasting.

BACKGROUND AND AIMS: During the month of Ramadan, Moslems refrain from drinking and eating between sunrise and sunset. This review aimed to analyze the effects of Ramadan fasting on physiological and behavioral variables in healthy subjects. METHODS: Articles included in this paper were taken from Medline, three international congresses on health and Ramadan, and in several cases from local journals. RESULTS: Ramadan fasting did not dramatically affect the metabolism of lipids, carbohydrates and proteins, or the daily mean of hormonal serum levels. An increase in serum urea and uric acid was frequently reported and this could be attributed to dehydration during this month. Some changes, such as the increase of HDL and apoprotein A1, and the decrease in LDL, could be beneficial for the cardiovascular system. However, the chronobiological studies have shown that Ramadan fasting affects the circadian distribution of body temperature, cortisol, melatonin and glycemia. The amplitude of most of these rhythms decreased and the acrophase shifted. Nocturnal sleep, daytime alertness and psychomotor performance were decreased. CONCLUSION: The major changes during Ramadan fasting are chronobiological and behavioral. They could be responsible for the high incidence of road traffic accidents and the reduction of working hours during the month of Ramadan.

Accidents, Traffic↗

PubMed2003

Daytime sleepiness during Ramadan intermittent fasting: polysomnographic and quantitative waking EEG study.

During the lunar month of Ramadan, Muslims abstain from eating, drinking and smoking from sunrise to sunset. We reported previously that Ramadan provokes a shortening in nocturnal total sleep time by 40 min, an increase in sleep latency, and a decrease in slow-wave sleep (SWS) and rapid eye movement (REM) sleep duration during Ramadan. During the same study, the effects of Ramadan intermittent fasting on daytime sleepiness were also investigated in eight healthy young male subjects using a quantitative waking electroencephalograph (EEG) analysis following the multiple sleep latency test (MSLT) procedure. This procedure was combined with subjective alertness and mood ratings and was conducted during four successive experimental sessions: (1) baseline (BL) 15 days before Ramadan, (2) beginning of Ramadan (R11) on the 11th day of Ramadan, (3) end of Ramadan (R25) on the 25th day of Ramadan, (4) recovery 2 weeks after Ramadan (AR). During each session, four 20-min nap opportunities (MSLTs) were given at 10:00, 12:00, 14:00 and 16:00 h and were preceded by rectal temperature readings. Nocturnal sleep was recorded before each daytime session. Subjective daytime alertness did not change in R25 but decreased in R11 at 12:00 h, and subjective mood decreased at 16:00 h, both in R11 and R25. During the MSLT, mean sleep latency decreased by an average of 2 min in R11 (especially at 10:00 and 16:00 h) and 6 min in R25 (especially at 10:00 and 12:00 h) compared with BL. There was an increase in the daily mean of waking EEG absolute power in the theta (5.5-8.5 Hz) frequency band. Significant correlations were found between sleep latency during the MSLT and the waking EEG absolute power of the fast alpha (10.5-12.5 Hz), sigma (11.5-15.5 Hz) and beta (12.5-30 Hz) frequency bands. Sleep latency was also related to rectal temperature. In conclusion, Ramadan diurnal fasting induced an increase in subjective and objective daytime sleepiness associated with changes in diurnal rectal temperature.

Adult↗