Washington: In a new study, scientists have investigated whether the people respond differently to caffeinated drinks that do or do not have sugar.

It is known that consuming caffeinated or sugary drinks can affect the body's metabolism, causing changes in heart and respiratory rate and weight gain.

The article by Elaine Rush, PhD and coauthors, Auckland University of Technology (Auckland, New Zealand), describes a study in which heart rate and carbon dioxide production (as a measure of respiration) were measured 30 minutes before and after individuals consumed a defined quantity of sugar, caffeine, or sugar and caffeine. Responses to the different treatments varied widely among individuals.

Dr. Patricia A. Broderick, Editor-in-Chief of the journal where the results are available, said that given the caveat that sugar itself affects brain reward just as caffeine does, and this effect would in itself cause variations, this was still an essential paper for the scientist and the lay person to read.

The study is published in Journal of Caffeine Research.