For thousands of years, humans rose with the sun and slept when it grew dark, with only the moon and stars or perhaps a fire to light the night. Waking and sleeping followed a natural 24-hour cycle called the circadian rhythm, which controls many physical processes in plants and animals. In humans, circadian rhythm affects body temperature, blood pressure, kidney function, and the circulation of hormones, among many other functions.
It can also affect the body’s response to cancer treatments, says Marina Antoch, PhD, Department of Pharmacology and Therapeutics. Dr. Antoch is a specialist in the relatively new field of chronobiology. (Chrono comes from the Greek word kronos, meaning “time.”)
Dr. Antoch and other scientists in the field are working to “find a way to use [circadian rhythm] to our benefit,” she says. In the ’80s and ’90s, some clinical trials showed that chronotherapy — giving cancer medications at specific times of day that coordinate with circadian rhythm — led to better results. But that method is not practical, she explains, “because those times could fall in the middle of the night.” While chronotherapy pumps have been invented to deliver medications automatically at any hour, they are bulky and too expensive, she adds.
So she and her Roswell Park team are exploring a different strategy. Their goal: to develop medications that can “reset the body clock” to a time when a patient’s cancer treatment will work best and cause fewer side effects. She and her colleagues are working to “find a way to use this system to our benefit. We are at the stage where we have some tools, some targets, and we can start applying what we know to practical applications.”
Darkness and Sleep: Why You Need Both
A little more than a century ago, electricity began making it easier to stay awake and active throughout the night. Today, lights, TVs, smartphones and computers expose us to unnaturally long periods of light and often keep us from getting a good night’s sleep. That’s a problem, because sleep is essential for our bodies to function properly.
We’re just beginning to recognize how health can be affected when the natural cycle of light and darkness gets out of whack. Studies have shown that women who work the night shift for many years are more likely than other women to develop breast cancer, for example. Disruption of the natural circadian rhythm has also been linked to sleeplessness, obesity, diabetes, mental illness — including depression — and other serious medical conditions.
So turn out the lights, pull down the shades, and get a good night’s sleep!
Learn more about circadian rhythm and your health from the National Institutes of Health.