Clamoring for votes in the presidential primaries has reached a fevered pitch, and the candidates are increasingly making mistakes brought on by lack of sleep. With 16- to 18-hour days the norm, chronic sleep deprivation is taking its toll.

Verbal blunders and hoarse voices are common. General Wesley Clark bragged to his staff that he “had not rested for a single day, unlike the other candidates.” But then Clark rapidly proved that lack of sleep impacts even generals — he stated at one campaign stop that he “did not believe Al Qaeda was involved in September 11,” when he meant to say Saddam Hussein, according to an article in The New York Times.

No one is immune to the perils of sleep deprivation, says Dr. Martin Moore-Ede of Circadian Technologies. And it's smart to realize your limits. During World War II, British Prime Minister Winston Churchill seemed never to sleep, making public appearances at 1 a.m. or 6 a.m. Little known was the fact that Churchill went to bed in his pajamas every afternoon for a long recuperative nap.