Adults who sleep no more than five hours a night are more likely to be heavy soda drinkers than people who get more rest, a U.S. study suggests. Soda is the main source of added sugar in the American diet, researchers note in the journal Sleep Health. Soda and lack of sleep are both independently associated with obesity, and sugar-sweetened beverages are also linked to rising rates of heart disease and diabetes, the authors write. Researchers examined survey data on almost 19,000 adults and found about 13 percent of participants slept five hours or less a night. What set these poor sleepers apart is they consumed 21 percent more sugar-sweetened drinks than adults who got a healthy seven to eight hours a night. Further analysis of the results by type of drink found the main association was with caffeinated non-diet sodas. “The most likely way in which soda consumption can negatively affect sleep is through ingesting the caffeine typically found in soda because caffeine blocks the binding of a particular chemical in the brain responsible for us feeling tired,” said lead study author Aric Prather of the University of California, San Francisco. Limitations of the analysis include the reliance on adults to accurately recall and report how long they slept and how much soda and other beverages they drank, the authors note. “It has been relatively well-established that people who don’t get enough sleep and those whose sleep is of poor quality are more likely to gain weight and become obese,” said Michael Grandner, director of the sleep and health research program at the University Of Arizona College Of Medicine in Tucson.