Coffee can keep you alert for hours

Does coffee keep drowsiness at bay and help one stay alert for hours? The answer is yes, according to tests carried out by a new optical instrument by a team of Swimburne University of Techology (SUT).

Natalie Michael and John Patterson of SUT's Sensory Neuroscience Lab set out to resolve the question.

"In our project we used the Australian-designed Optalert, which measures drowsiness by observing total duration of eye blinks and the ratio of amplitude and velocity of eye closure during blinking," said Patterson.

Optalert resembles a set of spectacle frames without lenses. Low intensity infra-red light is directed at the eyes. The infra-red is reflected back and detected by sensors in the frames. The pattern of light reaching the sensors changes as the eyes move and the subject blinks.

The participants were aged between 18 and 29, a primary target age group for road safety authorities because of their over-representation in drowsy driving incidents.

Test subjects were given either a placebo or a capsule containing 200 mg of caffeine, which is roughly equivalent to two cups of coffee, according to a SUT release. The study was published in the October issue of Psychopharmacology.

Those given the caffeine also showed improved reaction times, which like the improved alertness measured by the Optalert, persisted for about three hours.

Over the years recommendations for staying alert on long drives included stopping for a brisk walk, taking a power nap, and drinking coffee.

"However, road safety authorities were faced with conflicting evidence on the benefits of drinking coffee," Patterson said.

"Some research showed heightened alertness after caffeine administration, whereas other studies did not."

The Swinburne team collaborated with Murray Johns at Sleep Diagnostics and Caroline Owen who is now based at the Peter MacCallum Cancer Centre Research Division.

Last updated on Oct 30^th, 2008 at 12:01 pm IST--IANS