Intermittent fasting during Ramadan: does it affect sleep?

Authors

  • Ahmed S. BaHammam,

    Corresponding author
    1. University Sleep Disorders Centre, College of Medicine, King Saud University, Riyadh, Saudi Arabia
    2. National Plan for Science and Technology, King Saud University, Saudi Arabia
    • Correspondence Ahmed S. BaHammam, Professor of Medicine, Director, University Sleep Disorders Centre, College of Medicine, King Saud University, Box 225503, Riyadh 11324, Saudi Arabia. Tel.: 966-1-467-1492; fax: 966-1-467-9495; e-mails: ashammam2@gmail.com or ashammam@ksu.edu.sa

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  • Khalid Almushailhi,

    1. Sleep Disorders Centre, King Fahad Armed Forces Hospital, Jeddah, Saudi Arabia
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  • Seithikurippu R. Pandi-Perumal,

    1. Somnogen Canada Inc., Toronto, ON, Canada
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  • Munir M. Sharif

    1. University Sleep Disorders Centre, College of Medicine, King Saud University, Riyadh, Saudi Arabia
    2. National Plan for Science and Technology, King Saud University, Saudi Arabia
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Summary

Islamic intermittent fasting is distinct from regular voluntary or experimental fasting. We hypothesised that if a regimen of a fixed sleep–wake schedule and a fixed caloric intake is followed during intermittent fasting, the effects of fasting on sleep architecture and daytime sleepiness will be minimal. Therefore, we designed this study to objectively assess the effects of Islamic intermittent fasting on sleep architecture and daytime sleepiness. Eight healthy volunteers reported to the Sleep Disorders Centre on five occasions for polysomnography and multiple sleep latency tests: (1) during adaptation; (2) 3 weeks before Ramadan, after having performed Islamic fasting for 1 week (baseline fasting); (3) 1 week before Ramadan (non-fasting baseline); (4) 2 weeks into Ramadan (Ramadan); and (5) 2 weeks after Ramadan (non-fasting; Recovery). Daytime sleepiness was assessed using the Epworth Sleepiness Scale and the multiple sleep latency test. The participants had a mean age of 26.6 ± 4.9 years, a body mass index of 23.7 ± 3.5 kg m−2 and an Epworth Sleepiness Scale score of 7.3 ± 2.7. There was no change in weight or the Epworth Sleepiness Scale in the four study periods. The rapid eye movement sleep percentage was significantly lower during fasting. There was no difference in sleep latency, non-rapid eye movement sleep percentage, arousal index and sleep efficiency. The multiple sleep latency test analysis revealed no difference in the sleep latency between the ‘non-fasting baseline’, ‘baseline fasting’, ‘Ramadan’ and ‘Recovery’ time points. Under conditions of a fixed sleep–wake schedule and a fixed caloric intake, Islamic intermittent fasting results in decreased rapid eye movement sleep with no impact on other sleep stages, the arousal index or daytime sleepiness.

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