It's the news that millions of caffeine-addled workers won't want to hear: apparently, your costly coffee habit isn't making the blindest bit of difference to your levels of alertness. In fact, a new report from Bristol University suggests that all today's dosage is doing is counteracting the effect of caffeine withdrawal from the previous day's intake. The reseach does chime with the (admittedly anecdotal) evidence of the coffee-guzzling specimens at MT Towers, who have all experienced the 4pm slump. But now it's also being backed up by science (ish).
Blood samples were taken from 379 volunteers who were asked to avoid caffeine for 16 hours - after which they were either fed a caffeine pill or a placebo. They then took a slightly higher dose, or another placebo. The results showed that - you guessed it - those who took the caffeine pills were no more alert than those who had the placebo.
What's more, caffeine fiends who were given a placebo after abstaining from coffee for 16 hours (i.e. the ones who were practically chomping at the bit to inject the stuff into their eyeballs) actually felt less alert and had worse headaches than those who received their usual dose. Four unfortunate souls even had to quit the study because their heads were pounding too hard. And people who usually consumed little or no caffeine became more anxious after a dose, whereas medium-to-high level caffeine users didn't - suggesting that drinking it regularly helps build up a resistance to its anxiety-inducing effect.
So if you're a non-coffee drinker who only reaches for an espresso hit before that big meeting, this study suggests that you may be better off not bothering - it'll only leave you even more edgy and manic than you would have been otherwise. Equally, if coffee is simply something you drink to keep you going at work during the week, you probably ought to plough on with it over the weekend too - otherwise you're only going to feel worse come Monday morning.
Now, we tend to be a bit sceptical about this kind of PR-friendly 'science'. More educated souls will no doubt be able to advise us on the statistical significance and methodological rigour of this study, but one thing that immediately rings alarm bells is that a study out last month said almost the exact opposite. Researchers at the London School of Hygiene and Tropical Medicine found that caffeine helped improve workers' memory and reduced the number of mistakes they made; indeed, for those on long overnight shifts, drinking coffee had a similar effect to taking a ‘power nap' (as well as being far easier to explain to the boss, of course). So we'll probably stick with our espressos for the time being.
In today's bulletin:
Bank of England Governor turns down pay hike - as job gets harder?
BP coughs up for sand barriers as Tony Hayward admits to failings
Punctuality up, but profits down - Network Rail under fire again
John Vincent: Brands should be wonderful from the inside
Coffee power is just a bunch of froth?