A single blood draw can be used to determine someone’s internal circadian clock, information that’s useful for everything from treating cancer to getting better sleep, according to new research from the University of Colorado Boulder.
Studies have shown that looking at a person’s circadian rhythms, the name for the body’s internal sleep-wake cycle that repeats every 24 hours, can be used to improve outcomes for medical treatment like prescription drugs, undergoing chemotherapy and even surgery.
Individual circadian rhythms can vary by as much as six hours for a typical person, said senior author Christopher Depner, who conducted the study as an assistant professor of integrative physiology at CU Boulder. He is now an assistant professor at the University of Utah.
For people who work nights or long shifts, the difference can be as much as 12 hours from person to person.
Before now, patients would need to live in a lab in dim lighting for 24 hours and give saliva blood samples every hour to measure their melatonin levels in order to determine their individual circadian clock.
CU Boulder and CU Anschutz researchers found that looking at metabolites — things like amino acids and vitamins that are the byproducts of metabolism — in someone’s blood can provide similar information.
Researchers recruited 16 people to live in a sleep lab 24 hours a day for two weeks, controlling their sleeping and eating schedules as well as the light levels in their rooms.
By looking at metabolites as well as melatonin levels, researchers were able to identify metabolites that are related to circadian rhythms and predict the circadian phase within about an hour of the more involved test, according to the study published in the Journal of Biological Rhythms.
Circadian research is still in its early stages, Depner said, and needs more testing to see how it works in the real world — for example, does the same test work for people who aren’t in a tightly controlled environment for two weeks?
“The medical community is being a little bit slow to adopt this into practice, in part and admittedly because it’s early research, and there’s also a lot of logistical complications,” Depner said. “Providing medical care is difficult enough without saying we need to do it at this time of day.”
But Depner hopes that with additional evidence, health care providers will be convinced that circadian rhythms are an important part of treatment as well as regular checkups.
“It could help doctors know when to dose different treatments and drugs, and could help give them a clue if there is something wrong with your circadian rhythm, which is really closely related to sleep health,” Depner said. “Ultimately if this is something doctors can assess when you go in for your annual checkup, it could provide a better picture of overall health.”
This content was originally published here.