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A 50-year Harvard-backed study of nurses has turned everyday health advice into hard-to-ignore longevity evidence.
7 Smart Habits to Extend Your Life, From a Massive Harvard Study of More Than 100,000 Women Over 50 Years
Author: Bill Murphy Jr.
This is a story about proven, science-backed habits help you live longer from a big study of well over 100,000 people.
In the 1970s, a Harvard researcher named Frank Speizer was trying to understand the long-term effects of oral contraceptives. So, he did what a health researcher would do in those days. He asked male doctors to have their wives answer questions about their health.
Immediate problem: many doctors just filled out the forms on their wives’ behalf.
So Speizer and his team tried to think of how they could find a massive audience of women who were medically literate, conscientious, and willing to participate.
Um, hello? replied the entire U.S. nursing profession, metaphorically speaking.
The result: Speizer’s team sent letters to more than 170,000 women nurses in 1976, and 121,700 of them — more than 70% — agreed to answer questions about their health every two years for the rest of their lives.
The result has been one of the most important and productive research programs in the history of public health.
The study that keeps giving
The study is now run by Harvard T.H. Chan School of Public Health and Brigham and Women’s Hospital, with continuous funding from the National Institutes of Health.
A companion study enrolling more than 51,000 men was added in 1986, and some of the findings below draw on that combined dataset.
But the nurses came first. Without their participation, none of it exists. Here’s part of what their 50 years of data tells us: seven simple habits for a longer life.
1. Don’t smoke.
This one has never changed. A 2018 analysis of the combined dataset found that non-smokers lived significantly longer across every demographic studied. Other research has put the average cost of smoking at roughly seven years of life.
2. Maintain a healthy weight.
The same 2018 analysis found that maintaining a body mass index in the healthy range was consistently associated with longer life. Excess weight is tied to inflammation, cardiovascular strain, and metabolic disruption, all of which compound over decades.
3. Exercise at least 30 minutes a day.
Moderate daily physical activity was flagged one as well. Regular movement keeps your cardiovascular system efficient, your muscles functional, and your metabolic health in check. Separate research using the same dataset has found that consistent exercisers function biologically younger than their chronological age.
4. Drink alcohol only moderately, if at all.
The research consistently found moderate drinking — loosely defined as up to one drink per day for women, two for men — to be neutral to mildly beneficial compared to heavy drinking. This finding carries ongoing debate in the broader scientific literature, so maybe treat it as a general signal rather than a prescription.
5. Maintain a healthy diet.
The 2018 analysis defined this as scoring in the upper 40% on a diet quality index — which in practice means prioritizing vegetables, fruits, whole grains, and lean proteins, and limiting processed foods and added sugar.
6. Vary your exercise, not just the volume.
A more recent analysis of the same dataset, published in BMJ Medicine in January found that people who engaged in the broadest variety of physical activities — walking some days, lifting weights on others, gardening, cycling, playing tennis — had a 19% lower risk of premature death compared to those who exercised the same total amount but stuck to the same routines.
7. Drink two to three cups of caffeinated coffee a day.
Another study published earlier this year in JAMA, also drawing on the Nurses’ Health Study and Health Professionals Follow-Up Study, found that people who drank two to three cups of caffeinated coffee daily had an 18% lower risk of developing dementia compared to those who drank little or none. Tea showed similar patterns. Decaf did not.
The honest caveat
None of these findings prove causation. People who exercise in varied ways, drink moderate coffee, and eat well may share other traits — stronger social connections, better sleep, lower chronic stress — that also contribute to longer lives.
But after 50 years and more than 100,000 participants, they establish patterns that are very hard to dismiss.
The nurses who answered Frank Speizer’s letter in 1976 are mostly in their 80s and 90s now — or gone. But they gave the world a cleaner picture of what a longer life tends to look like.
As it happens, Tuesday is National Nurses Day in the United States. It feels like a good moment to acknowledge that the debt runs deeper than most people realize.
Credits: TCA, LLC.