Glucose control upon waking is unaffected by hourly sleep fragmentation during the night, but is impaired by morning caffeinated coffee

Harry A. Smith, Aaron Hengist, Joel Thomas, Jean Philippe Walhin, Philippa Heath, Oliver Perkin, Yung Chih Chen, Javier T. Gonzalez, James A. Betts*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Morning coffee is a common remedy following disrupted sleep, yet each factor can independently impair glucose tolerance and insulin sensitivity in healthy adults. Remarkably, the combined effects of sleep fragmentation and coffee on glucose control upon waking per se have never been investigated. In a randomised crossover design, twenty-nine adults (mean age: 21 (sd 1) years, BMI: 24·4 (sd 3·3) kg/m2) underwent three oral glucose tolerance tests (OGTT). One following a habitual night of sleep (Control; in bed, lights-off trying to sleep approximately 23.00-07.00 hours), the others following a night of sleep fragmentation (as Control but waking hourly for 5 min), with and without morning coffee approximately 1 h after waking (approximately 300 mg caffeine as black coffee 30 min prior to OGTT). Individualised peak plasma glucose and insulin concentrations were unaffected by sleep quality but were higher following coffee consumption (mean (normalised CI) for Control, Fragmented and Fragmented + Coffee, respectively; glucose: 8·20 (normalised CI 7·93, 8·47) mmol/l v. 8·23 (normalised CI 7·96, 8·50) mmol/l v. 8·96 (normalised CI 8·70, 9·22) mmol/l; insulin: 265 (normalised CI 247, 283) pmol/l; and 235 (normalised CI 218, 253) pmol/l; and 310 (normalised CI 284, 337) pmol/l). Likewise, incremental AUC for plasma glucose was higher in the Fragmented + Coffee trial compared with Fragmented. Whilst sleep fragmentation did not alter glycaemic or insulinaemic responses to morning glucose ingestion, if a strong caffeinated coffee is consumed, then a reduction in glucose tolerance can be expected.

Original languageEnglish
Pages (from-to)1114-1120
Number of pages7
JournalBritish Journal of Nutrition
Volume124
Issue number10
DOIs
Publication statusPublished - 2020 Nov 28

Keywords

  • Caffeine
  • Coffee
  • CYP1A2
  • Glucose
  • Insulin
  • Polymorphisms
  • Sleep fragmentation

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics

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