The blood test that tells you if you are a night owl or a lark in the morning

According to a new study, life-threatening diseases linked to our "internal clock" could be avoided with a simple blood test.

Researchers at Northwestern University in Chicago have identified a link between "circadian misalignment" and diabetes, obesity, depression, heart disease and asthma.

And in doing so, they have developed a blood test – called TimeSignature – that determines the "time" inside the body.

The team found that some people's internal clocks are synchronized with real time – but others are not synchronized and are considered misaligned.

The researchers said that a misaligned "circadian rhythm" can lead to illnesses and health problems.

Examples include everything from heart disease, diabetes to Alzheimer's disease – which can be avoided with the new discovery.

The processes throughout the body are managed by an internal biological clock, which directs the circadian rhythm, such as the sleep-wake cycle.

In the study, an algorithm was used to trace subjects' blood every two hours – before the level of present genes was examined.

This allowed the researchers to train a computer to predict the time at which specific patterns of genes were present.

Out of 20,000 genes measured, 40 patterns emerged – and can be easily identified by the new test – with the lifestyle of a person adjusted accordingly.

Lead author Rosemary Braun, assistant professor of preventive medicine at the Feinberg School of Medicine at the university, said: "Various groups have been trying to get a circadian blood test, but nothing about it." 39 has been as accurate or easy to use.

"This is a much more precise and sophisticated measure than identifying the lark in the morning or at night.

"The TimeSignature allows us to evaluate a person's biological clock in an hour and a half."

Previously, accurate measurements could only be obtained through an expensive and time-consuming process of taking samples every hour over several hours.

When the blood test becomes clinically available, it will also provide physicians with optimal time for medication.

The co-author, Professor Phyllis Zee, head of Sleep Medicine in Neurology at Feinberg, said, "This really is an integral part of personalized medicine – so many drugs have optimal times for dosing.

"It's essential to know what time it is in your body to get the most effective benefits.

"The best time to take the medication for high blood pressure or chemotherapy or radiation may be different than anyone else.

"Before, we had no clinically feasible method for assessing the time of healthy people and people with diseases.

"Now we can see if a disturbed clock is correlating with various diseases and, more importantly, whether it can predict who will get sick."

A link between circadian misalignment and diabetes, obesity, depression, heart disease, and asthma has been identified in preclinical research.

Subsequently, Dr. Zee plans to improve health and treat diseases by aligning circadian clocks with people who are not in sync with external time.

She added: "Circadian timing is a modifiable risk factor for improving cognitive health, but if we can not measure it, it is difficult to know if we have made the right diagnosis.

The software and algorithm are freely available to other researchers so that they can evaluate the physiological time in a person's body.

The findings were published in the journal Proceedings of the National Academy of Sciences (PNAS).