If you’re an entrepreneur who isn’t as healthy as you’d like to be, what actions should you take to improve? Ask just about anyone this question, and you’ll get roughly the same answer: exercise more and eat healthier. Sure, some folks might recommend Crossfit, or vitamins, or healing crystals. But personal tastes aside, most of us share a basic understanding that health is largely determined by what you put in your body and how much you move and rest it

This understanding is intuitive, and it’s also what scientists used to believe. At least, until some unexpected study results started rolling in. 

Diet and exercise matter. So does mindset 

Take, for example, a team conducting research on how diet affects heart health using rabbits. All of the genetically identical animals were given the same high-fat kibble, but some rabbits mysteriously had much healthier hearts than others. Stumped, the scientists started investigating, and they discovered the healthier bunnies were being cared for by a kind-hearted research assistant who gave them lots of cuddles. The others were ignored. 

Same food, same genes, same exercise regime, totally different health outcomes. The explanation wasn’t physical. It was mental. And it’s not just bunnies. Another recent study showed that those with better mental health live an average of five years longer, controlling for all the usual factors that affect longevity like diet, smoking, and exercise levels. 

These are two of a large number of such studies, many of which were rounded up by Harvard psychologist Ellen Langer, a pioneering researcher into the link between mindset and health, in her new book, The Mindful Body. A recent review on the Greater Good Science Center highlights more mind-blowing research from the book: 

  1. Youthful environment, youthful body. This famous study had a memorable setup and striking conclusions: In 1979, Langer and her Harvard colleagues invited healthy elderly men to spend a week in a location they’d carefully designed to look and feel exactly like the 1950s, when the men were in their prime. After a week of watching Ed Sullivan and listening to Perry Como, what happened to the men? Their hearing, memory, posture, and physical dexterity all improved. After being surrounded by reminders of their youth, they were measurably more youthful. 

  2. Feeling needed matters. In another study, some nursing home residents were given small responsibilities, such as caring for a plant, while others continued to have nothing demanded of them but choosing between shuffleboard and Jeopardy. Those who took on responsibilities were twice as likely to still be alive 18 months later.  

  3. Mindset affects physiology (part 1). Exercise is exercise, right? Common sense suggests it shouldn’t matter what you think about while doing it. But that’s not what science shows. When researchers told housekeepers to think of their work as healthful physical exercise similar to working out in a gym, they lost more weight and had lower blood pressure, even though they did the exact same amount of physical labor.  

  4. Mindset affects physiology (part 2). Mindset can help you when it comes to physical health. It can also harm you. After performing tests, Stanford researchers told some study subjects their genetic profile would make exercising more difficult. Except the tests were an elaborate pantomime, and the results were made up. Nevertheless, the subjects’ bodies behaved as if the results were real — those who were told their genes would make exercise difficult tired more easily during workouts. Completely fictional stories changed how people’s bodies performed

  5. Does time fly or drag? We’ve all experienced how time can feel like it stretches or contracts. A fun afternoon passes in a flash, while a boring workday seems 19 hours long. Langer’s research also shows time perception influences physiology. Her team had diabetes patients play video games while checking a clock regularly, only sometimes the researchers slowed the clock down and sometimes speeded it up. Blood tests revealed those who thought more time had passed burned more energy. Subjective perception of time changed people’s metabolism. 

These results should be enough to convince you that your physical health and your mindset are not separate things. How you think and feel has very real — and very big — impacts on your body. This doesn’t mean, of course, you can will away every malady. If your doctor tells you to take antibiotics, eat more veggies, or get a vaccination, do it. But don’t underestimate the power of mindset, either.  

What exactly does that translate to in terms of everyday advice? Investing in the basics of good mental health, like quality relationships, continued learning, and positive thinking seems like a solid bet, but the Greater Good article offers a deeper dive into Langer’s recommendations if you’re interested. They include things like being skeptical of blanket health prescriptions that don’t suit your life or personality and avoiding comparisons to others. 

The opinions expressed here by Inc.com columnists are their own, not those of Inc.com.