Black Tea and Stress: Can One Influence the Other?
The claim that drinking tea is a natural method of stress relief is one that has circulated for centuries. However, until recently no viable scientific study had been conducted to verify its authenticity. A study conducted out of the University College London focused on the effects of black tea, not the benefits of green tea or herbal tea, on men's overall stress levels. What they found has been widely considered.
The study, which was published in the October issue of the medical journal Psychopharmacology, followed 75 young men who were considered regular tea-drinkers. The men were then split into two groups: one of which was given a caffeinated, fruit-flavored placebo identical in taste to the tea beverage offered to the other group, though theirs did not contain the active black tea ingredients found in the second groups' concoction. In designing their tea beverage, the researchers accounted for the potentially "comforting effect" of tea by masking it with scents and flavors not normally associated with the beverage.
During the six-week study, both groups were required to perform challenging tasks and endure stressful situations (i.e. threat of unemployment) while being monitored for any changes in their cortisol, blood pressure, blood platelets, and self-rated levels of stress.
What the researchers found was that men in both groups were equally susceptible to stress during these challenges, as almost all experienced substantial increases in blood pressure and heart rate as was indicated by their own subjective levels of stress.
However, what was most interesting about the results was that nearly an hour after performing the task, men belonging to the group drinking authentic black tea had levels of cortisol - a stress-related hormone - that were 20% lower than their counterparts in the placebo group (both groups dropped 47% and 27% respectively).
In addition, blood platelet activation, high levels of which are linked to blood clotting and risk of heart attack, was also lower amongst the black tea drinkers. These men also self-reported lower stress levels during the recovery period.
What Does it all Mean?
Professor Andrew Steptoe of the UCL Department of Epidemiology and Public Health said that although the study is important in advancing our understanding of the link between stress relief and tea remedies, the complexity of tea - which contains several ingredients known to influence the brain - necessitates more research to narrow in on the exact benefits (if any) of drinking the brew.
He did add, however, that although black tea "does not appear to reduce the actual levels of stress we experience, tea does seem to have a greater effect in bringing stress hormone levels back to normal," adding, "This has important health implications because slow recovery following acute stress has been associated with a greater risk of chronic illnesses such as coronary heart disease."
Put more simply, to all the tea drinkers out there: keep it up.