The participants were next asked to complete a 90-minute test during the afternoon low-energy period. The test assessed their level of sleepiness and ability to concentrate.

"Around 70 minutes after consumption, there was a worsening of sleepiness --delayed reaction time, increased lapses in attention -- following the consumption of a high-sugar drink, in comparison to a placebo," Anderson said.

Her conclusion: Highly-sugared drinks without caffeine do not counteract sleepiness beyond perhaps a short sugar rush. In fact, they appear to boost drowsiness.

"These drinks are of little benefit to sleepy people," Anderson said. "Caffeinated drinks, even sugary ones, are much better for counteracting detrimental effects of sleepiness."

One nutrition expert agreed that sugar won't help push energy levels past the initial minutes-long sugar rush, and even caffeine won't help you stay awake beyond a few hours.

"Energy drinks are a misnomer," said Lona Sandon, an assistant professor of clinical nutrition at the University of Texas Southwestern Medical Center at Dallas and spokeswoman for the American Dietetic Association. "Sure, they provide energy in the form of calories, usually from some form of a simple sugar," she added.

Sandon explained that simple sugars are digested, absorbed and metabolized very quickly, so the energy they contain doesn't last long. "Some energy drinks may have just enough caffeine to stimulate your central nervous system and give you a false sense of feeling energized for a short period of time," Sandon said. "Keep in mind, a dose of caffeine large enough to have an energizing effect -- about 1 regular soda or cup of coffee -- will only last about 3 hours."

According to the Texas expert, there is a more lasting and healthy means of staying fresh: good sleep and a healthful diet.

"To improve a feeling of having energy, start by getting plenty of rest, fluids, and fuel your body with quality nutrients from fresh fruits, vegetables, whole grains and lean protein sources," Sandon said. "A balanced diet, including carbohydrate, fat, and protein, will keep you feeling satisfied longer."

Immigrants Healthier Than Native New Yorkers

  FRIDAY, July 21 (HealthDay News) -- Foreign-born residents of New York City generally arrive in the city healthier than U.S.-born residents, according to a city health department report released Friday.

But the longer they stay, the more unhealthy they become, the researchers added.

"Exposure to the U.S. environment appears to increase their risk of obesity and may contribute to a decline in general health," City Health Commissioner Dr. Thomas R. Frieden said in a prepared statement. "Language barriers, immigration status and environmental factors such as greater availability of unhealthy food and decreased physical activity may worsen health among some immigrant New Yorkers," he added.

The Health of Immigrants in New York City report found that foreign-born adults are less likely to smoke, drink alcohol excessively, be obese or be diagnosed with HIV (the virus that causes AIDS). They also have a lower infant mortality rate than Americans living in the city.

However, many immigrants -- especially those who speak Spanish -- face significant challenges accessing health care and preventive care, the report found. This appears to result in poorer health for them the longer they live in the United States.

According to the study, foreign-born adults living in New York City are less likely than U.S.-born residents to have their blood pressure checked (86 percent vs. 92 percent) or to have their cholesterol checked (67 percent vs. 77 percent). They're also less likely to have receive colon cancer screenings (44 percent vs. 53 percent) and Pap tests (73 percent vs. 84 percent).

Among the other findings in the report:

• Adults born in Ukraine are twice as likely to smoke as other foreign-born New Yorkers. Adults born in Italy, Poland, Mexico, and Russia also have high smoking rates.
• People from Panama and Honduras are more likely to be obese than the overall foreign-born or U.S.-born populations. Adults born in Korea are least likely to be obese.
• Adults born in Honduras are three times more likely to report having diabetes than overall foreign-born and U.S.-born populations.
• The rate of new HIV diagnoses among adults born in Haiti is nearly four times higher than that of the overall foreign-born population and 1.5 times that of U.S.-born New Yorkers.

"In a city where one out of every three New Yorkers was born abroad and almost half of every two workers is foreign-born, this report is a huge resource for improving the health of families and communities," Immigration Affairs Commissioner Guillermo Linares said in a prepared statement.