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A naturalistic investigation of the effects of day-long consumption of tea, coffee and water on alertness, sleep onset and sleep quality.

Abstract

RATIONALE

The effects of caffeine, especially caffeinated coffee, on human performance have been extensively studied. However, few studies have been naturalistic representations of how tea/coffee is normally consumed in terms of dose and time of consumption.

OBJECTIVES

This study investigated the effects of day-long consumption of tea, coffee and water on cognitive and psychomotor performance, and sleep quality at night.

METHODS

Thirty healthy volunteers received equal volume drinks equivalent to either 1 or 2 cups of tea (containing 37.5 mg or 75 mg caffeine), or coffee (75 mg or 150 mg caffeine), or water, in a randomised five-way crossover design. Drinks were administered on four occasions during the day (0900, 1300, 1700 and 2300 hours). A psychometric battery consisting of critical flicker fusion (CFF), choice reaction time (CRT) and subjective sedation (LARS) tests, was administered pre-dose and at frequent time points post-dose. The Leeds Sleep Evaluation Questionnaire (LSEQ) was completed each morning and a wrist actigraph was worn for the duration of the study.

RESULTS

Caffeinated beverages maintained CFF threshold over the whole day (P<0.05), independent of caffeine dose or beverage type. During the acute phase of beverage ingestion, caffeine significantly sustained performance compared to water after the first beverage for CFF and subjective sedation (P<0.05), and after the second beverage for the Recognition component of the CRT task (P<0.05). Additionally, there were significant differences between tea and coffee at 75 mg caffeine after the first drink. Compared to coffee, tea produced a significant increase in CFF threshold between 30 and 90 min post-consumption (P<0.01). However, following the second beverage caffeinated coffee at 75 mg significantly improved reaction time (P<0.05), compared to tea at the same dose, for the Recognition component of the CRT task. Caffeinated beverages had a dose dependent negative effect on sleep onset (P<0.001), sleep time (P<0.001) and sleep quality (P<0.001).

CONCLUSIONS

These results indicate that ingestion of caffeinated beverages may maintain aspects of cognitive and psychomotor performance throughout the day and evening when caffeinated beverages are administered repeatedly. This study also demonstrates that day-long tea consumption produces similar alerting effects to coffee, despite lower caffeine levels, but is less likely to disrupt sleep. Other differences between tea and coffee were more subtle, and require further investigation.

Authors+Show Affiliations

,

HPRU Medical Research Centre, University of Surrey, Guildford, UK.

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Source

Psychopharmacology 149:3 2000 Apr pg 203-16

MeSH

Adult
Analysis of Variance
Caffeine
Central Nervous System Stimulants
Coffee
Cognition
Cross-Over Studies
Female
Flicker Fusion
Humans
Linear Models
Male
Psychomotor Performance
Reaction Time
Sleep
Tea
Water

Pub Type(s)

Clinical Trial
Journal Article
Randomized Controlled Trial

Language

eng

PubMed ID

10823400

Citation

Hindmarch, I, et al. "A Naturalistic Investigation of the Effects of Day-long Consumption of Tea, Coffee and Water On Alertness, Sleep Onset and Sleep Quality." Psychopharmacology, vol. 149, no. 3, 2000, pp. 203-16.
Hindmarch I, Rigney U, Stanley N, et al. A naturalistic investigation of the effects of day-long consumption of tea, coffee and water on alertness, sleep onset and sleep quality. Psychopharmacology (Berl). 2000;149(3):203-16.
Hindmarch, I., Rigney, U., Stanley, N., Quinlan, P., Rycroft, J., & Lane, J. (2000). A naturalistic investigation of the effects of day-long consumption of tea, coffee and water on alertness, sleep onset and sleep quality. Psychopharmacology, 149(3), pp. 203-16.
Hindmarch I, et al. A Naturalistic Investigation of the Effects of Day-long Consumption of Tea, Coffee and Water On Alertness, Sleep Onset and Sleep Quality. Psychopharmacology (Berl). 2000;149(3):203-16. PubMed PMID: 10823400.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - A naturalistic investigation of the effects of day-long consumption of tea, coffee and water on alertness, sleep onset and sleep quality. AU - Hindmarch,I, AU - Rigney,U, AU - Stanley,N, AU - Quinlan,P, AU - Rycroft,J, AU - Lane,J, PY - 2000/5/24/pubmed PY - 2000/9/2/medline PY - 2000/5/24/entrez SP - 203 EP - 16 JF - Psychopharmacology JO - Psychopharmacology (Berl.) VL - 149 IS - 3 N2 - RATIONALE: The effects of caffeine, especially caffeinated coffee, on human performance have been extensively studied. However, few studies have been naturalistic representations of how tea/coffee is normally consumed in terms of dose and time of consumption. OBJECTIVES: This study investigated the effects of day-long consumption of tea, coffee and water on cognitive and psychomotor performance, and sleep quality at night. METHODS: Thirty healthy volunteers received equal volume drinks equivalent to either 1 or 2 cups of tea (containing 37.5 mg or 75 mg caffeine), or coffee (75 mg or 150 mg caffeine), or water, in a randomised five-way crossover design. Drinks were administered on four occasions during the day (0900, 1300, 1700 and 2300 hours). A psychometric battery consisting of critical flicker fusion (CFF), choice reaction time (CRT) and subjective sedation (LARS) tests, was administered pre-dose and at frequent time points post-dose. The Leeds Sleep Evaluation Questionnaire (LSEQ) was completed each morning and a wrist actigraph was worn for the duration of the study. RESULTS: Caffeinated beverages maintained CFF threshold over the whole day (P<0.05), independent of caffeine dose or beverage type. During the acute phase of beverage ingestion, caffeine significantly sustained performance compared to water after the first beverage for CFF and subjective sedation (P<0.05), and after the second beverage for the Recognition component of the CRT task (P<0.05). Additionally, there were significant differences between tea and coffee at 75 mg caffeine after the first drink. Compared to coffee, tea produced a significant increase in CFF threshold between 30 and 90 min post-consumption (P<0.01). However, following the second beverage caffeinated coffee at 75 mg significantly improved reaction time (P<0.05), compared to tea at the same dose, for the Recognition component of the CRT task. Caffeinated beverages had a dose dependent negative effect on sleep onset (P<0.001), sleep time (P<0.001) and sleep quality (P<0.001). CONCLUSIONS: These results indicate that ingestion of caffeinated beverages may maintain aspects of cognitive and psychomotor performance throughout the day and evening when caffeinated beverages are administered repeatedly. This study also demonstrates that day-long tea consumption produces similar alerting effects to coffee, despite lower caffeine levels, but is less likely to disrupt sleep. Other differences between tea and coffee were more subtle, and require further investigation. SN - 0033-3158 UR - https://www.unboundmedicine.com/medline/citation/10823400/A_naturalistic_investigation_of_the_effects_of_day_long_consumption_of_tea_coffee_and_water_on_alertness_sleep_onset_and_sleep_quality_ L2 - https://medlineplus.gov/caffeine.html DB - PRIME DP - Unbound Medicine ER -