C. Lloret-Linares, MD, Internist
Does a single cup of coffee at dinner alter the sleep? A controlled cross-over randomised trial in real-life conditions
Article first published online: 15 JUN 2012
© 2012 The Authors. Nutrition & Dietetics © 2012 Dietitians Association of Australia
Nutrition & Dietetics
Volume 69, Issue 4, pages 250–255, December 2012
How to Cite
LLORET-LINARES, C., LAFUENTE-LAFUENTE, C., CHASSANY, O., GREEN, A., DELCEY, V., MOULY, S. and BERGMANN, J. F. (2012), Does a single cup of coffee at dinner alter the sleep? A controlled cross-over randomised trial in real-life conditions. Nutrition & Dietetics, 69: 250–255. doi: 10.1111/j.1747-0080.2012.01601.x
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
- Issue published online: 20 DEC 2012
- Article first published online: 15 JUN 2012
- Accepted October 2011
- healthy people;
- real-life condition;
- sleep disorder
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.