Body’s Clock Never Adjusts to DST

The e-mail is on a different machine so I don’t know who to credit for this, but they said that their life is ruled by the clock while their body is ruled by the sun. German researchers are reporting that our internal body clocks never really adjusts to Daylight Saving Time.

“When you change clocks to daylight savings time, you don’t change anything related to sun time,” explained lead researcher Till Roenneberg of Ludwig-Maximilians-University in Munich. “This is one of those human arrogances — that we can do whatever we want as long as we are disciplined. We forget that there is a biological clock that is as old as living organisms, a clock that cannot be fooled. The pure social change of time cannot fool the clock.”

People’s circadian rhythm — the body’s internal clock — follows the sun and changes depending on where you live. It actually changes in four-minute intervals, exactly the time it takes for the sun to cross one line of longitude, Roenneberg explained.

“The circadian clock does not change to the social change,” Roenneberg said. “During the winter, there is a beautiful tracking of dawn in human sleep behavior, which is completely and immediately interrupted when daylight savings time is introduced in March,” he said. It returns to normal this year when standard time returns on Nov. 4, he added.