NORTHBROOK, Ill., March 4 (UPI) -- Most U.S. physicians report they aren't getting the sleep they need to function at their best, a study found.

The survey, issued by the American College of Chest Physicians Sleep Institute, found 70 percent of physicians reported needing at least seven to eight hours of sleep to function at their best, yet, on average, physicians reported sleeping 6.5 hours a night and 21 percent reported not feeling refreshed upon waking at least a few nights a week.

Ninety-three percent of physicians said they drink at least one caffeinated beverage a day compared with 81 percent in the general population but 83.6 percent of physicians claim to be in very good or excellent health compared with 56 percent of the general population.

"Call hours during training and in the practice of medicine desensitize physicians to the importance of sleep. The pervasive message is that sleep is optional or dispensable," Dr. Barbara Phillips of the ACCP Sleep Institute said in a statement.

"Self-sacrifice also may be seen as part of the lifestyle. This may impact physicians' awareness of their own, and their patients', sleep deprivation lifestyles."

In a randomized, Internet-based questionnaire, the Sleep Institute surveyed 5,000 U.S. physicians about sleep habits. A total of 581 responses were received.