Does a single cup of coffee at dinner alter the sleep? A controlled cross-over randomised trial in real-life conditions

Authors

  • Célia LLORET-LINARES,

    Corresponding author
    1. Department of Internal Medicine, Assistance Publique-Hôpitaux de Paris, University of Paris VII, Hôpital Lariboisière, Paris, France
      C. Lloret-Linares, Service de Médecine Interne A—Unité de Recherches Thérapeutiques, Hôpital Lariboisière, 2 rue Ambroise Paré, 75010 Paris. France. Email: celialloret@yahoo.fr
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  • Carmello LAFUENTE-LAFUENTE,

    1. Department of Internal Medicine, Assistance Publique-Hôpitaux de Paris, University of Paris VII, Hôpital Lariboisière, Paris, France
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  • Olivier CHASSANY,

    1. Department of Internal Medicine, Assistance Publique-Hôpitaux de Paris, University of Paris VII, Hôpital Lariboisière, Paris, France
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  • Andrew GREEN,

    1. Yorkleigh Sirgery, Cheltenham, Gloucestershire, UK
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  • Véronique DELCEY,

    1. Department of Internal Medicine, Assistance Publique-Hôpitaux de Paris, University of Paris VII, Hôpital Lariboisière, Paris, France
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  • Stéphane MOULY,

    1. Department of Internal Medicine, Assistance Publique-Hôpitaux de Paris, University of Paris VII, Hôpital Lariboisière, Paris, France
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  • Jean François BERGMANN

    1. Department of Internal Medicine, Assistance Publique-Hôpitaux de Paris, University of Paris VII, Hôpital Lariboisière, Paris, France
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  • C. Lloret-Linares, MD, Internist

  • C. Lafuente-Lafuente, MD, PhD, Cardiologist

  • O. Chassany, MD, PhD, Internist

  • A. Green, MD, General Practitioner

  • V. Delcey, MD, Internist

  • S. Mouly, MD PhD, Internist, Professor

  • J.F. Bergmann, MD, Internist, Associate Professor

C. Lloret-Linares, Service de Médecine Interne A—Unité de Recherches Thérapeutiques, Hôpital Lariboisière, 2 rue Ambroise Paré, 75010 Paris. France. Email: celialloret@yahoo.fr

Abstract

Aim:  To report changes in the quality of sleep after drinking an evening cup of either caffeinated or decaffeinated coffee, in healthy subjects in everyday life.

Methods:  Sixty-three healthy men and women, who considered themselves to be caffeine sensitive were included in a double-blind, cross-over trial, randomised to receive either caffeinated coffee containing 90 mg of caffeine, or, as control, a dose of decaffeinated coffee containing 4.5 mg caffeine, taken after dinner. The primary outcome measure was the degree of sleep disturbance, scored on a visual analogue scale, ranging from 0 (excellent sleep) to 100 (very disturbed sleep). Ancillary criteria were patients' reported estimate of sleep latency, and how often the subjects reported waking.

Results:  Mean age of subjects was 30.5 ± 12 years. The quality of sleep was significantly worse with caffeinated (mean 30.8 ± 22.7) than with decaffeinated coffee (mean 19.5 ± 16.9), P = 0.001. Caffeinated coffee also significantly increased the sleep latency (mean difference 17 ± 31 minutes, P < 0.001) and the frequency of waking (mean 1.3 vs 0.8 episodes in the night, P = 0.006) compared with decaffeinated coffee.

Conclusions:  Even a single cup of caffeinated coffee consumed before bedtime in real-life conditions causes a deterioration in the quality of sleep in caffeine-sensitive subjects.

Ancillary