Introduction: Caffeine is widely used to reverse alertness and performance decrements. However, caffeine's effects on subsequent recovery sleep and post-recovery performance are not well documented and, therefore, were evaluated.
Methods: Six habitually low (LC: < or = 100 mg x d(-1)) and three habitually high (HC: > or = 400 mg x d(-1)) caffeine users completed a randomized crossover design. After 20 h of wakefulness, repeated doses of caffeine gum [0 (placebo) mg, 100 (low dose) mg, or 300 (high dose) mg] were administered at 03:00, 05:00, and 07:00. At 10:00 (27 h sleep deprivation) subjects slept for 8 h, followed by Psychomotor Vigilance Task (PVT) administration at 33 and 65 min post-awakening.
Results: Low dose caffeine increased stage 1 minutes only. However, high dose caffeine impaired sleep maintenance (reduced total sleep time/increased wake) and reduced sleep depth (increased stage 1 minutes/percentage and slow-wave sleep (SWS) latency, and reduced SWS minutes during the first third of the sleep period). With high dose caffeine, LC users had less SWS percentage as compared with HC users. The HC users had reduced stage 2 percentage with high dose caffeine as compared with placebo and low dose caffeine. Caffeine dose and habitual caffeine use did not influence post-recovery sleep PVT performance.
Discussion: Caffeine exerts mild deleterious dose-response effects on recovery sleep following total sleep deprivation, primarily early in the sleep period, with potential recovery from these effects after sufficient sleep as suggested by lack of post-recovery sleep performance deficits. Habitual caffeine use appears to minimally reduce caffeine effects.
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Pharmaceuticals (Basel)
December 2024
Department of Physiology, Faculty of Medicine, Istanbul Medeniyet University, 34700 Istanbul, Türkiye.
With increasing interest in plant-based compounds that can enhance sleep quality without the side effects of caffeine, Alpinia galanga (AG) has emerged as a promising herbal supplement for improving mental alertness. This study assessed the impact of water-soluble AG extract on sleep quality; the activity of GABAergic, glutamatergic, and serotonergic receptors; and concentrations of dopamine and serotonin in the brains of mice. The study employed two experimental models using BALB/c mice to examine the impact of pentobarbital-induced sleep and caffeine-induced insomnia.
View Article and Find Full Text PDFInt J Biol Sci
January 2025
Department of Neonatology and Pediatric Intensive Care, Children's Hospital University of Bonn, Bonn, Germany.
J Hum Nutr Diet
February 2025
Reproductive Medical Center, The First Affiliated Hospital of Guangxi Medical University, Nanning, China.
Background: Caffeine has been suggested to have a relationship with endometriosis as a widely consumed psychoactive substance, although findings are inconsistent.
Objective: This study explored the potential associations and threshold effects between caffeine intake and endometriosis using cross-sectional data from the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2006.
Methods: The study included 248 women with endometriosis and 2944 without, aged 20-50 years.
Front Nutr
December 2024
Department of Endocrinology, Fuwai Central China Cardiovascular Hospital, Zhengzhou, China.
Background: This is the initial investigation assessing the association between caffeine consumption through diet and circulating Klotho concentrations, with Klotho being recognized as a key biomarker of healthspan and aging.
Methods: This cross-sectional analysis utilized data from 11,169 adults who participated in the National Health and Nutrition Examination Survey (NHANES). Caffeine consumption was evaluated using 24-h dietary recall interviews by trained professionals, and serum Klotho concentrations were measured via an enzyme-linked immunosorbent assay (ELISA).
J Int Soc Sports Nutr
December 2025
The Center for Applied Health Sciences, Canfield, OH, USA.
Creatine monohydrate supplementation (CrM) is a safe and effective intervention for improving certain aspects of sport, exercise performance, and health across the lifespan. Despite its evidence-based pedigree, several questions and misconceptions about CrM remain. To initially address some of these concerns, our group published a narrative review in 2021 discussing the scientific evidence as to whether CrM leads to water retention and fat accumulation, is a steroid, causes hair loss, dehydration or muscle cramping, adversely affects renal and liver function, and if CrM is safe and/or effective for children, adolescents, biological females, and older adults.
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