Do you have an expiration date? A new study that examines the body's circadian rhythms suggests that while we might not be able to pinpoint the day you'll die, we might be able to get a rough idea of the time of day. Here's what you should know:
First off: What's a circadian rhythm?
The body's internal clock that regulates what time we wake up, when we feel most awake, and what time we start feeling sleepy. Each individual's rhythm is sensitive to outside factors like daylight and time zone changes, though recent studies have demonstrated that gene mutations can also cause a person's circadian rhythms to vary. That's why some people are "morning people" while others can barely get themselves out of bed. And now, a new study from the neurological department of the Beth Israel Deaconess Medical Center (BIDMC) in Boston claims that we can use these gene mutations to assess what time of day a person might die.
How was this research conducted?
Researchers combed through 15 years of data from a sleep study originally conducted at Rush University in Chicago. This study took a look at roughly 500 seniors over age 65, all of whom wore an actigraph, which closely tracks your sleeping habits. Many of the subjects also had their DNA collected, and had physical and psychological evaluations performed. Before the study was finished, many of the participants had also died — providing researchers with many subjects' exact time of death.
What did researchers discover?
First, certain nucleotides helped determine each subject's natural sleeping patterns. For example: People with the genotype "A-A" tended to be early risers, waking up a full hour earlier than people on the other end of the spectrum, or late sleepers born with the genotype "G-G." Most of us fall somewhere in the middle with a gene configuration "A-G" — a full 48 percent of us are born with this broader, A-G configuration and tend to wake up sometime between the early birds and the late sleepers.
How do these gene patterns relate to death?
This is where things get a little weird: People born with either an A-A or A-G genotype tended to die just before 11 a.m; Late sleepers with a G-G genotype, on the other hand, generally died just before 6 p.m.
Why is this?
"Virtually all physiological processes have a circadian rhythm" — including death, says BIDMC Chief of Neurology Clifford Saper. Researchers speculate that as the elderly patients inched closer to death's door, their usual social commitments became less of a factor in their daily lives, allowing their circadian rhythms to assert more authority — and the times of their death to be dictated, at least in part, by their genes.