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.
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 placebo.
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.
Via: nationalpost.com