Taking a coffee break at work may actually hinder employees’ ability to do their jobs and undermine teamwork instead of boosting it, suggests a new research. Dosing up on caffeine is particularly unhelpful to men, (62) their emotions and hampering their ability to do certain tasks, (63) a report by psychologists Lindsay St Claire and Peter Rogers at Bristol University in the UK. Many people take coffee breaks at work believing this will reduce their feelings of stress. But theories about the effects of caffeine are (64) . Some studies suggest caffeine can worsen anxiety and trigger stress, (65) others show it boosts confidence, alertness, and (66) , making certain tasks easier. But this latest report, (67) by the UK’s Economic and Social Research Council on Friday, (68) the view that coffee worsens stress, (69) in men, and makes people less co-operative when working in teams. St Claire and Rogers decided to (70) caffeine’s effects on work stress after hearing a story. A man described how he and a group of normally cooperative colleagues went (71) a business trip to the US. Unlike in the UK, coffee was freely (72) and the team over-indulged. Within days their stress had (73) and they believe the extra caffeine had disrupted their working relationships, and (74) their working ability. The Bristol team tested caffeine’s effects on 32coffee-drinkers. They told them they would be given a caffeinated coffee that would (75) their performance, or a caffeinated coffee which causes stress-like side-effects, or decaffeinated coffee. However, (76) to the volunteers, only half the drinks contained 200 mg of caffeine and the other half contained none. The (77) then carried out two stressful tasks. "Unexpectedly, men told their coffee ’contained caffeine, which enhances performance’ had higher heart rates and used less (78) coping strategies--that is showed more stress," say the pair. They add that caffeine’s effects on men maybe worse because men may feel more (79) or challenged by some tasks than women, and caffeine (80) their stress. St Claire warns against people being "tempted into having extra coffee". "And if you are (81) a business meeting, go a bit easy on the percolator(煮咖啡壶), or you might actually find weird things going wrong from your attempt at hospitality," she adds.