| Disease | 19 HEALTHY VOLUNTEERS INGESTED 400 ML BLACK TEA, COFFEE, CAFFEINATED WATER, DECAFFEINATED TEA OR PLAIN WATER ON THREE OCCASIONS THROUGH THE DAY (0900, 1400 AND 1900 HOURS). A 2 X 2 FRACTORAL DESIGN WITH CAFFEINE (0, 100 MG) AND BEVERAGE TYPE
(WATER, TEA) WAS EMPLOYED, WITH COFFEE (100 MG CAFFEINE) AS A POSITIVE ENTERNAL CONTROL, BASED ON A 5-WAY CROSSOVER. A PSYCHOMETRIC TEST BATTERY COMPRISING CRITICAL FLICKER FUSION (CFF), CHOICE REACTION TIME (CRT), SHORT-TERM MEMORY (STM) AND
SUBJECTIVE SEDATION (LARS) WAS PERFORMED AT REGULAR INTERVALS THROUGHOUT THE DAY, AND INTENSIVELY SO, IMMEDIATELY FOLLOWING EACH BEVERAGE. CONSUMPTION OF TEA COMPARED TO WATER WAS ASSOCIATED WITH TRANSIENT IMPROVEMENTS IN PERFORMANCE (CFF)
WITHIN 10 MIN OF INGESTION AND WAS NOT AFFECTED BY THE TIME OF DAY. CAFFEINE INGESTION WAS ASSOCIATED WITH A RAPID (10 MIN) AND PERSISTENT REDUCTION IN SUBJECTIVE SEDATION VALUES (LARS), AGAIN INDEPENDENT OF TIME OF DAY, BUT DID NOT ACUTELY
ALTER CFF THRESHOLD. OVER THE WHOLE DAY, CONSUMPTION OF TEA RATHER THAN WATER, AND OF CAFFEINATED COMPARED TO DECAFFEINATED BEVERAGES, LARGELY PREVENTED THE STEADY DECLINE IN ALERTNESS (LARS) AND COGNITIVE CAPACITY OBSERVED WITH WATER INGESTION. |