Caffeine addicts get no real perk from morning cup
| By Manager Online | 15 June 2010 11:26 |
 |
 | | This photo retrieved June 7, 2010 is from www.google.co.th. Caffeine only brings regular coffee drinkers to the baseline levels of alertness. | | |
June 14, 2010
LONDON (Reuters) – Caffeine addiction is such a downer that regular coffee drinkers may get no real pick-me-up from their morning cup, according to a study by British scientists.
Bristol University researchers found that drinkers develop a tolerance to both the anxiety-producing and the stimulating effects of caffeine, meaning that it only brings them back to baseline levels of alertness, not above them.
"Although frequent consumers feel alerted by caffeine, especially by their morning tea, coffee, or other caffeine-containing drink, evidence suggests that this is actually merely the reversal of the fatiguing effects of acute caffeine withdrawal," wrote the scientists, led by Peter Rogers of Bristol's department of experimental psychology.
The team asked 379 adults -- half of them non/low caffeine consumers and the other half medium/high caffeine consumers -- to give up caffeine for 16 hours, and then gave them either caffeine or a dummy pill known as a placebo.
|
 | | A waitress serves coffee to a customer in a coffee shop in Jakarta July 23, 2008. REUTERS/Supri | | | Participants rated their levels of anxiety, alertness and headache. The medium/high caffeine consumers who got the placebo reported a decrease in alertness and increased headache, neither of which were reported by those who received caffeine.
But measurements showed that their post-caffeine levels of alertness were actually no higher than the non/low consumers who received a placebo, suggesting caffeine only brings coffee drinkers back up to "normal."
The researchers also found that people who have a genetic predisposition to anxiety do not tend to avoid coffee.
In fact, people in the study with a gene variant associated with anxiety tended to consume slightly larger amounts of coffee than those without it, Rogers wrote in a study in the Neuropsychopharmacology journal, published by Nature.
This suggests that a mild increase in anxiety "may be a part of the pleasant buzz caused by caffeine," he said.
(Reporting by Kate Kelland; editing by Peter Graff) |
The Dictionary of Computer Science, Engineering, and TechnologyPermanent Magnet Motor Technology (Electrical and Computer Engineering)Broadcast Engineering: Electrical engineering, Computer engineering, Information technology, Radio, Television, Broadcasting, Audio engineering, RF engineering, Subset, Studio, TransmitterHydro GIS: Theory and Lessons from the Vietnamese Delta (Environmental Science, Engineering and Technology)High-Speed Photodiodes in Standard CMOS Technology (International Series in Engineering and Computer Science) (The Springer International Series in Engineering and Computer Science)CFD Modeling and Analysis of Different Novel Designs of Air-Breathing Pem Fuel Cells (Energy Science, Engineering and Technology)Structural Dynamic Systems: Computer Aided Design and Engineering (Engineering, Technology & Applied Science)Introduction to High Power Pulse Technology (Series in Electrical and Computer Engineering)The Information Security Dictionary: Defining the Terms That Define Security for E-Business, Internet, Information and Wireless Technology (The Kluwer ... Series in Engineering and Computer Science)Any Time, Anywhere Computing: Mobile Computing Concepts and Technology (Springer International Series in Engineering and Computer Science) (The ... Series in Engineering and Computer Science)
ไม่มีความคิดเห็น:
แสดงความคิดเห็น