It’s a fact of nature that not everyone goes to bed at the same time. All of our body clocks are set at least a little different, and there’s actually a good evolutionary reason for it. But, wouldn’t it be cool to know exactly what time your body is set to? Science may have found a way.
The first simple blood test to identify your body’s precise internal time clock as compared to the external time has been developed by Northwestern Medicine scientists. The test, TimeSignature — which requires only two blood draws – can tell physicians and researchers the time in your body despite the time in the external world. For instance, even if it’s 8 a.m. in the external world, it might be 6 a.m. in your body.
“This is a much more precise and sophisticated measurement than identifying whether you are a morning lark or a night owl,” said lead author Rosemary Braun, assistant professor of preventive medicine (biostatistics) at Northwestern University Feinberg School of Medicine. “We can assess a person’s biological clock to within 1.5 hours.
“Various groups have tried to get at internal circadian time from a blood test, but nothing has been as accurate or as easy to use as TimeSignature,” Braun said.
Previously, measurements this precise could only be achieved through a costly and laborious process of taking samples every hour over a span of multiple hours. The new test for the first time will offer researchers the opportunity to easily examine the impact of misaligned circadian clocks in a range of diseases from heart disease to diabetes and Alzheimer’s disease. When the blood test eventually becomes clinically available, it also will provide doctors with a measurement of an individual’s internal biological clock to guide medication dosing at the most effective time for his or her body.
The software and algorithm are available for free to other researchers so they can assess physiological time in a person’s body. Northwestern has filed for a patent on the blood test.
“This is really an integral part of personalized medicine,” said coauthor Dr. Phyllis Zee, chief of sleep medicine in neurology at Feinberg and a Northwestern Medicine neurologist. “So many drugs have optimal times for dosing. Knowing what time it is in your body is critical to getting the most effective benefits. The best time for you to take the blood pressure drug or the chemotherapy or radiation may be different from somebody else.”