(Ivanhoe Newswire) -- That sugar rush might give you a quick burst of energy, but it may later make you more tired than you already were.

A new study from the University of Loughborough, England, reveals one hour after having a high-sugar, low-caffeine drink participants had slower reactions and more lapses in concentration than those who drank a decaffeinated beverage without carbohydrates.

Researchers studied 10 volunteers who had only five hours of sleep the day before. One hour after they ate a light lunch participants had either an energy drink containing 42 grams of sugar and 30 milligrams of caffeine or a beverage with no sugar and no caffeine. Researchers then tested their sleepiness and ability to concentrate.

Results show there was no difference in reaction times or error rates for the first 30 minutes. But 50 minutes after they had the drinks, performance of participants who had the energy drink started to deteriorate, and they became significantly sleepier.

"A 'sugar rush' is not very effective in combating sleepiness, so avoid soft drinks that contain lots of sugar but little or no caffeine," reports study co-author Professor Jim Horne. "A much better way to combat sleepiness is to have a drink that contains more useful amounts of caffeine and combine this with a short nap."