Daylight-saving time does more than just rob us of an hour of sleep. When folks all across the country reset their clocks Sunday morning, they will also be forcing a vital part of their brains to do something it really doesn't want to do.
The biological clock, found in just about everything from pond scum to humans, is the key player in a complex system that controls the respiratory system, blood pressure and heartbeat, sleep-wake cycles and even such seemingly unrelated problems as medical toxicity and depression.
Only in recent years have scientists begun to understand this vital clock, which is only about the size of a kernel of corn. It has a dramatic impact on our mental and physical well-being. Yet we ask it routinely to reset itself as we zip about the world, traveling across multiple time zones. And on the first Sunday of every April, we tell it to spring forward one hour.
"It's a force that is manifested in every aspect of our daily existence," says biologist David Glass of Kent State University, who has been studying the clock for about 15 years.
Glass likens the clock to an orchestra conductor.
"You have a conductor and maybe 100 people who are playing various instruments," he says. "Music is rhythmical, just like our daily activities. We have a master clock located in the brain, and that clock is like the conductor.
"In our body we have hundreds of subordinate oscillators, or pacemakers, which are like all the players in the orchestra. Without the conductor, or master clock, you would end up with nothing but noise."
So much needs to be learned about how the biological clock ticks that laboratories have sprung up around the world. The University of Houston, for example, has five different labs with nearly 40 researchers.
Among the findings reported by various researchers:
The clock speeds up as we age, which may be why many seniors have trouble sleeping.
People who awaken early have a clock that is set about two hours earlier than most others.
A healthy biological clock may increase longevity.
Even algae has a biological clock, and when researchers at Vanderbilt University disrupted the clock the algae grew much more slowly than normal algae.
Biological clocks are universal, in plants, insects and mammals but are dominated by different genes.
If they are so important, is there anything we can do to keep them functioning properly? Can we help them adjust to time changes and jet lag?
The answer, Glass says, is yes. Like most of our organs, the biological clock depends partly on our life style.
Glass uses hamsters as his volunteers, and his lab was the first in the country to show that the biological clock regulates the release of serotonin, a critical compound that causes blood vessels to constrict, stimulates smooth muscles, and plays a role in the transmission of impulses between nerve cells.
The hamsters used in the research are healthy and happy, Glass says, and they exercise regularly on a wheel. It turns out that when the animals are running, they release more serotonin, and "serotonin plays a major role in terms of controlling the timing of the clock itself," he adds.
The same thing happens in humans.
"If you were to go out and run, or even take a brisk walk, we know that would stimulate serotonin release in the brain," Glass says. "That has a number of different effects, including for a lot of folks, alleviating depression."