Well, thankfully, Jill Suite from Greater Good Magazine did read the book and helped break it down for us.

In 1979, Harvard researcher Ellen Langer invited elderly men to spend a week at a retreat designed to remind them of their younger days, surrounded by the art, music, food, games, décor, and more from the late 1950s. Afterward, the men were tested and found to have made significant gains in hearing, memory, dexterity, posture, and general well-being. It was as if being in a place signaling their younger days made them physiologically “younger.”

Maybe you, too, have had an experience where your mind seemed to affect your health. It turns out there’s a reason for that, according to Langer, author of the new book The Mindful Body. Your mind is not separate from your physiology, and changing your mindset in various ways can lead to a happier, healthier life.

Though her book is called The Mindful Body, it’s not a book promoting mindfulness meditation, per se. Instead, it’s an argument against mindlessly accepting that our health and cognition will invariably decline, especially as we age, and the importance of letting go of limiting beliefs that keep us from being our most vital selves.

“I believe the mind and body comprise a single system, and every change in the human being is essentially simultaneously a change at the level of the mind (that is, cognitive change) as well as the body (a hormonal, neural, and/or behavioral change),” she writes. “When we open our minds to this idea of mind-body unity, new possibilities for controlling our health become real.”

How your mind influences your body

Langer recounts dozens (if not hundreds) of studies in her book illustrating how our mindset affects our physiology. For example, in one study, nursing home residents who were encouraged to take responsibility for simple decisions or care for a plant were twice as likely to be alive 18 months later. In another, housekeepers lost more weight, had lower blood pressure, and had lower body mass indices when they were prompted to consider their work as comparable to exercising in a gym, compared to other housekeepers given general health information but doing the same work. In still another, giving people information about their (fictitious) level of risk for obesity affected their metabolism and how they felt about exercise and hunger (regardless of their actual level of risk).

In one mind-blowing study, Langer had people with type 2 diabetes play video games while checking a clock every 15 minutes. Unbeknownst to the participants, some clocks ran on time, while others ran either twice as fast or twice as slow. Based on blood readings, those whose clocks ran faster (who believed more time had passed) had lower blood sugar levels than any other participants—meaning, they were using up energy faster than people in groups with slower clocks. The participants’ perception of time affected their energy consumption more than the actual time that had passed!

Despite these kinds of findings, the effects of our minds on our bodies are often called a “placebo effect” in research and dismissed as irrelevant, says Langer. In fact, she argues, many studies find that a placebo is as effective or outperforms a drug, but those studies are rarely published. This makes it hard to understand and harness a placebo’s potential for healing.

“What we should be learning from these studies is not that a particular drug is ineffective but rather how effective the placebo may have been,” she writes.

In one review of research, for example, researchers concluded that anti-depressants and anti-anxiety medication were no more effective than placebos. But why were the placebos effective? No one really knows, though it could be due to expectations of getting better rather than any effects from the drugs themselves. As evidence for the power of suggestion, Langer and her colleagues have found that you can improve your vision—seemingly an intractable condition—when you’re told it’s possible to do so with practice.

In other words, expectations matter.

How to harness the power of your mind

What all this means for our lives is a bit tricky, as Langer isn’t suggesting we abandon all medical research and start healing ourselves with our minds alone. Nor is she suggesting we put everyone in an artificial living environment to pretend that we are young again, or that we are in total control of our health. But she does think we can use the power of our minds to change our health and well-being in ways that are mostly untapped.

How can you use your mind to help yourself? To start, she suggests adhering to a few basic principles:

1. Question authority—meaning, don’t follow all recommendations just because an expert tells you to. Life is uncertain, and we are individuals, with our own unique makeup. So, for example, if your doctor tells you that being one point above the threshold for “high cholesterol” requires a complete change of diet or medication, you might question that before complying. After all, there is little real difference between someone one point above versus one point below the threshold, and that reading may change one day to the next.

2. Recognize that what counts as “risky” is different from person to person. One person’s risk is another’s reasonable plan of action, making sense to them in the moment (based on their self-knowledge and available resources). Behavior can’t be judged in a vacuum. So, for example, backcountry skiing may seem risky to you and not worth doing, but it could be great fun and adventurous for someone else.

3. Approach predictions with skepticism. The future is never completely knowable. If things are looking bad, you shouldn’t assume you’re on a trajectory that will only get worse. In fact, many dire predictions turn out to be wrong or are later disproven. For example, not all people with pre-cancer go on to get cancer, nor is surgery or chemotherapy always necessary. In fact, some chemotherapy treatments once commonly used have been discontinued because they do more harm than good.

4. Understand how our choices are never completely “right” or “wrong.” You should focus less on regretting “bad decisions” and more on how to make your choices, whatever they are, work out for you. Look for the positive. For example, if you move to a new city and don’t love it right away, you shouldn’t regret your decision to move. Instead, you can focus on what the new city offers—maybe new forms of entertainment, different people to meet and befriend, or closer public parks to enjoy.

5. Avoid social comparisons or ranking yourself. This is never good for our health or happiness. Instead of chasing achievement relative to others, focus on finding meaning in what you’re already doing—whatever it is. For example, caretaking the elderly can be boring or stressful, and is often poorly compensated. But when you do it out of love or a sense of providing dignity to others, it can feel more rewarding.

As Langer notes, “When we make these shifts in our thinking, our relationships with others and ourselves improve, and our stress lessens, all in the service of improving our health.”

Be mindful of how everything changes

Langer also cautions us to be more mindful of our everyday experiences. She doesn’t mean meditate more—she wants us to notice variations in our state of being. If we pay attention to how our pain, energy levels, poor mood, or other symptoms of illness are changing over time, moment to moment, we can break out of rigid, fixed beliefs that we are sick or damaged and notice the moments when we feel happy, healthy, or pain-free.

“Paying attention to variability helps us see that symptoms come and go, which helps us home in on the situations and circumstances that might contribute to these fluctuations so that we might exert some control over them,” she writes. For example, if you pay mindful attention to variances in knee pain during the day, you may notice that you feel better after a walk and make a plan to take more walks.

In the book, she presents several studies where people with various ailments were trained to notice more variability in their symptoms—when they felt better or worse over time—and had better outcomes as a result. For example, studies have found that mindful attention to variability has helped people control their own heart rate, helped ALS patients experience less pain and physical impairment, and helped expectant mothers enjoy greater well-being—as well as better outcomes for their newborns.

Perhaps Langer’s most provocative advice is reserved for doctors and others who treat illness, mental or physical. When delivering news to patients, she writes, practitioners would do well to present diagnoses and prognoses in tentative ways, allowing for the possibility of being wrong and for more optimistic outlooks. By doing so, she says, practitioners could help patients hold loosely the labels that make them see themselves in fixed ways and become, instead, more mindful, active participants in their own health care.

“When health professionals mindlessly assume every symptom is part of the disease they’ve diagnosed or are treating, they give up the possibility to potentially influence the course of a patient’s illness,” she writes. “Diagnoses, while useful, direct attention to only a fraction of lived experience; context influences our physical responses.”

To that end, Langer hopes that all of us can hold certainty more lightly, not accept dire prognoses without question, pay more attention to how our experiences change over time, and be open to using the power of our minds to help ourselves enjoy life more.

“Once we recognize that mindless decisions from the past are limiting us, there is little stopping us from redesigning the world to better fit our current needs rather than using yesterday to determine today and tomorrow,” she writes.