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Here’s a sad story: The other day, my wife and I woke up and realized we were out of coffee.
Honestly, if you want to throw a wrench into the Murphy household and hamper our routine, take away the coffee.
Anyway, the story ends much better; I threw on a baseball hat and drove to the supermarket down the road.
But it also reminded me of a study I’ve wanted to share here, led by researchers at Tulane University who analysed data on 40,725 Americans and their coffee-drinking habits over nearly a decade.
In short, they found something remarkable about when people drink their coffee.
The study, supported by the U.S. National Heart, Lung, and Blood Institute, was published in January in the European Heart Journal. It determined that people who drink coffee primarily in the morning had significantly lower mortality rates than people who either don’t drink coffee at all—or who drink it throughout the entire day.
Examples:
“Research so far suggests that drinking coffee doesn’t raise the risk of cardiovascular disease, and it seems to lower the risk of some chronic diseases, such as Type 2 diabetes,” said Lu Qi, who led the study at Tulane University’s School of Public Health and Tropical Medicine. “Given the effects that caffeine has on our bodies, we wanted to see if the time of day when you drink coffee has any impact on heart health.”
The study included adults from the U.S. National Health and Nutrition Examination Survey between 1999 and 2018. Researchers identified two distinct patterns of coffee drinking among participants:
The remaining 50% of participants either didn’t drink coffee or didn’t fit cleanly into either pattern.
Over a median follow-up period of 9.8 years, researchers recorded 4,295 deaths from all causes, 1,268 deaths from cardiovascular disease, and 934 deaths from cancer.
After adjusting for factors like total caffeine intake (both caffeinated and decaffeinated coffee), sleep hours, diet, and other lifestyle variables, the morning-type pattern emerged as significantly protective—while the all-day-type pattern did not.
Here’s where it gets even more interesting.
Among morning coffee drinkers, the protective effect increased with the amount of coffee consumed.
People who drank moderate amounts (two to three cups per day) or heavy amounts (more than three cups per day) in the morning showed the strongest associations with lower mortality risk.
But among all-day coffee drinkers, no such association appeared.
Drinking more coffee throughout the day didn’t provide any measurable mortality benefit at all.
“Coffee drinking timing significantly modified the association between coffee intake amounts and all-cause mortality,” the researchers wrote. “Higher coffee intake amounts were significantly associated with a lower risk of all-cause mortality in participants with morning-type pattern but not in those with all-day-type pattern.”
The researchers proposed two potential mechanisms to explain their findings.
First, consuming coffee in the afternoon or evening may disrupt circadian rhythms.
A previous clinical trial found that heavy coffee consumption in the afternoon or evening reduced peak nighttime melatonin production by 30% compared with controls.
Lower melatonin levels have been linked to higher oxidative stress, elevated blood pressure, and increased inflammation—all risk factors for cardiovascular disease.
Second, coffee’s health benefits come largely from anti-inflammatory compounds.
Pro-inflammatory markers in the blood follow a circadian pattern—they’re typically highest in the morning and gradually decline until reaching their lowest levels around 5 p.m.
Therefore, drinking coffee when inflammation is naturally highest may amplify its anti-inflammatory benefits more effectively than spreading consumption throughout the day.
We should acknowledge that this study shows correlation, not causation. It’s possible that morning coffee drinkers have other habits or characteristics researchers didn’t identify that contribute to their longevity.
That said, this study takes its place alongside a growing body of research suggesting that coffee consumption is associated with significant health benefits.
Among them:
Beyond that, the risk of heart disease starts to increase.
I’m not going to suggest you should race out and start pounding five cups of coffee before noon.
But for those of us who already drink coffee in the morning—and I don’t think the Murphy household is a rarity at all in this—it’s reassuring.
Just don’t run out. That’s when the drama starts.
And keep a baseball cap near the door, in case you forget and have to make an early shopping trip.
—Bill Murphy Jr.
This article originally appeared on Fast Company’s sister publication, Inc.
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