Effect of Caffeine on Stress Levels and Teamwork

“Taking a coffee break at work may actually sabotage employees’ ability to do their jobs and undermine teamwork instead of boosting it, suggests new research.” So begins an article in New Scientist. We thought coffee breaks reduce stress. Have you noticed however, that after drinking coffee, stressful personal interactions do actually become more tense? Men tend to speak much louder, escalating into yelling or shouting.

A pair of scientists from Bristol University were inspired by a report of an attendee at one of their stress workshops.

The man traveled to the U.S. with his workmates. They found coffee more available in the U.S. than it is in the U.K. The men in his entourage took advantage of the readily available source of their favorite drug. He related that “within days their stress levels had escalated and they believe the extra caffeine had disrupted their working relationships, and impaired their working ability.”

Back in the ‘lab,’ these two scientists set up a scenario to test the effects of java on people’s stress levels and working relationships. They gave subjects a beverage containing 200 milligrams of caffeine (about 2 cups of espresso) or a caffeine-free cup.

The most pronounced effects seemed to be on the men in the study. Men had higher heart rates and used less adaptive coping strategies under the influence of caffeine. They had more difficulty during a public speaking task after drinking coffee. However, their performance in mathematics was not affected by the beverage. Surprisingly, levels of alertness were similar whether or not participants drank caffeinated beverages.

Given a group ‘desert survival task,’ taking a coffee break reduced indicators of stress, but reduced men’s ability to perform as a team. The effect was more pronounced in men than their female counterparts. Jim Lane of Duke University, theorizes that men may be more threatened by stressful situations. Stress is amplified by caffeine.

A separate report from BBC News explains that it is indeed possible to get too much coffee: “Indulging in a few mugs too many could result in symptoms such as restlessness, nervousness, excitement, insomnia, nausea, vomiting and a flushed face. The symptoms of a serious overdose include delirium and seizures.”

Caffeine overdose can be fatal, in the short term, if not in the long run. “Death from an extreme overdose would tend to be due to ventricular fibrillation -- an uncoordinated contraction of heart muscles, which could stop blood pumping.” the BBC article reports. Toxicity reactions may occur with consumption of as few as seven cups of coffee per day, the article explains. Individual sensitivity may vary, however. Some people may exhibit symptoms from less java, while others may be able tolerate a bit more.

Caffeine is an addictive drug. Those who consume at least 600 to 750 milligrams of caffeine per day will find it difficult to go without their daily fix.

How much caffeine is in that cup? The BBC reports: “The highest natural caffeine content is found in filter coffee, a mug of which contains about 120 mg of caffeine. Instant coffee contains roughly 75 mg and espresso 107 mg.”

They do not explore the effect of long term use of excessive amounts of caffeine consumption. Some studies suggest a link between habitually large consumption of coffee and fibromyalgia.

Caffeine is by far the most commonly consumed psychoactive substance. Perhaps, when it is time to take a break, it would be better to take a walk, drink ordinary H2O, and take several deep breaths than to hit Starbucks.

References:

newscientist
bbc