The Doctor Is Within

We put a lot of faith in the medical establishment these days, and doctors can certainly tell us a great deal about our constitution. But there's one person who knows more about your health than any doctor—you. As it turns out, the answer to one deceptively simple question—"How would you rate your own health?"—predicts disease and longevity more accurately than even the most thorough medical records.

Why are our own health assessments so dead on? Maybe because we monitor our ups and downs and symptoms 24/7—a perspective no doctor has access to.

"We know things that physicians cannot physically detect," says Yael Benyamani, a health psychologist at Tel-Aviv University in Israel. Fatigue and appetite fluctuations, for example, can be symptoms of declining health, and you're likely to be much more attuned to them than is your doctor.

Decades of studies show that people who say their health is poor are likely to die sooner than those who rate their health excellent, even after controlling for how sick people actually are. The association is independent of medical diagnoses, symptoms or level of disability. In other words, the way we rate our own health reflects something beyond what doctors have the power to diagnose. But what?

Part of the answer lies in how your body reacts to stress. A study in the International Journal of Behavioral Medicine found that people who considered themselves healthy had wider fluctuations in their levels of the stress-fighting hormone cortisol: low levels most of the time, with big spikes during tense situations. People who felt unhealthy had high levels of cortisol all the time—a symptom of chronic stress, which is linked to cardiovascular disease, among many other problems.

Measures of psychological stress showed the same pattern: People with good coping skills or strong social support perceived themselves to be in better health—and they were. The researchers conclude that the way a person handles life's inevitable strains is a big part of how he judges his well-being.

Our assessments don't just predict health outcomes; they may cause them too. "It's possible that the frame of mind of being a healthy person leads you to be more active, take better care of your health and take more preventive measures," Benyamani says. By the same token, getting stuck in the rut of considering yourself unhealthy could incline you toward picking up risky behaviors like smoking or slacking off on eating well and working out.

Research also suggests that believing you are healthy can have a positive influence on your endocrine and immune systems. "There may be ways in which pursuing a healthy behavior leads to health outcomes by totally other routes," explains Daniel Bailis, associate professor of psychology at the University of Manitoba. "A behavior like exercise may have positive health implications not only because you're more fit, but because you're creating a healthier state of the self through multiple pathways."

While our ratings of our own health predict our actual health regardless of culture, race, gender and age, people arrive at their answers differently. A study in Medical Care found that people under age 25 tend to focus on their health behaviors, like whether they work out or smoke cigarettes, while people over 25 think more about their health problems. This makes sense, since people generally don't have to deal with serious health problems until later in life. It also reveals that people intuitively concentrate on the health considerations most salient to them. This is another possible reason their responses are so predictive.

There's also evidence that men's health ratings predict health slightly better than women's do. Women tend to incorporate their current mood into their appraisals, and moods shift much more quickly than health.

To stay healthy, use intuition to guide your behavior. Changes are much more likely to stick if the motivation behind them is intrinsic. Let's say you want to work out more. Thoughts like, "Exercise is enjoyable," will fare much better than, "My doctor thinks I need to get in shape."

And don't try to fit into a prescribed behavior change. Make the change fit you. Bailis notes, "What's important is to recognize that there are strategies that may not be the latest diet, the latest craze. They might suit a person's tastes and desires, even if they don't exactly conform to a set level of calorie intake or activity that the professionals may be recommending. "

Experts hasten to issue a word of warning: All these findings don't mean you should start disregarding your doctor's advice. But you may be taking a risk by closing off another crucial source of information—yourself. Don't dismiss that inner stethoscope.