Nutrition and exercise boost mood and brain power. An angry disposition can bring on back pain. A positive attitude can aid in recovery from disease. Stress can kill you.

Think your mind and body aren’t connected? Think again. And read on.

Denis Waitley advises athletes, astronauts and CEOs on how to make the most of the mind-body connection to give them a mental edge—a vital edge. As the former head of psychological training for the U.S. Olympic team, Waitley helped athletes sharpen their focus with a routine that begins by saying: “I’m relaxed, focused and feel great. My muscles are well-trained and powerful. My lungs are strong and clear. My stomach is warm.”

Athletes also recite to themselves a few upbeat trigger words just before an event. So a gymnast preparing for the vault might think, “speed, explode, rotate, plant,” which tells her body to run down the runway, fully extend on the side of the horse, rotate in air and nail the landing brilliantly.

That’s the opposite of telling yourself: “I hope I don’t fall. I hope I don’t get nervous. I’m getting an upset stomach. The floor exercises are distracting.” Or what a coach years ago told a figure skater: Get tough, get firm, bear down, don’t fall. A bad mistake, Waitley says.

“That’d be like telling a high-wire walker: ‘Don’t fall. Very windy, windy day. No net. Remember—no net.’ That would make you immediately tighten up.”

All of these negative thoughts might be going through an inexperienced person’s mind. Waitley calls them “ANTs”—abstract negative thoughts. They’re like ants at a picnic, distracting and possibly ruinous even though they should be of little consequence. “We live in a society crammed full of these abstract negative thoughts,” he says. “That’s why it’s so important to relax, concentrate, focus, and then get this mindset of a champion, this mental training going for you.”

How Positive Attitude Boosts Physical Health
Attitude is everything. When you have a positive attitude, there is a real commitment that you will perform at a much higher level, says Dr. Michael Roizen, Cleveland Clinic’s chief wellness officer and co-author with Dr. Mehmet Oz of the best-selling YOU series of books. And remember, he says, you always get a “do-over.” You can always start right now.

Consider the nuns: Researchers read the autobiographical essays of 180 U.S. nuns written back in the 1930s and ’40s when they were young (average age 22) and found that those nuns who used optimistic verbiage went on to live longer lives—an average of seven years longer than more pessimistic nuns. What’s more, the more adjectives and ideas they crammed into the final 10 sentences of their autobiographies, the better their minds proved to be in old age. Alzheimer’s disease was confirmed only in nuns whose writings were relatively skimpy.

Optimists age well and their health is unusually good, according to psychologist Martin Seligman’s book Learned Optimism, which notes, “Literally hundreds of studies show that pessimists give up more easily and get depressed more often.” One study found patients deemed pessimistic in a personality study 30 years earlier had a 19 percent increase in the risk of mortality. In a 2008 Duke University study, cardiac patients who were pessimistic about their recovery were twice as likely to die early as those who were optimistic.

Journalist Norman Cousins overcame a crippling disease in part by watching funny Marx brothers’ movies and Candid Camera episodes and laughing out loud, all of which created a positive scenario that fostered healing as described in his 1979 best-seller, Anatomy of an Illness as Perceived by the Patient.

Many studies show that cancer patients who visualize healthy cells eating or taking over cancer cells helps them battle certain forms of the disease. Many health professionals encourage patients to use such visualization techniques.

Tips for nurturing your inner optimist: “I write three thank-you notes at night. It’s one of the last things I do whether at work or at home,” Roizen says. Start a gratitude journal to recall why you’re grateful. (A bonus for you: Fifteen minutes of daily gratitude can make stress hormones plummet, he says.)

How Stress Affects Your Health
We’re programmed to respond to challenges by fight or flight, which was extremely useful back when the challenge was fleeing a woolly mammoth—but nowadays the stress response is dysfunctional, Roizen explains. Your adrenaline pumps. Blood pressure goes up. The heart races. Again and again.

Chronic stress is a poison. It’s toxic—both for the brain and the body. It’s generally the greatest ager of your body with far-reaching implications. It stops neurogenesis (the creation of new brain cells) and increases the odds of cancer, hormonal problems, gastrointestinal issues, depression and the aging of arteries. Acute stress makes you think more clearly and get focused; chronic stress brings migraines, tremors, headaches, anxiety and a six-fold increased risk of heart attack. Nagging worries over unfinished tasks burn you out and cause exhaustion.

Tips for de-stressing: Meditate, develop close friendships, and, a favorite of Roizen’s, feel empathy. When a motorist cuts off Roizen in traffic, he imagines that poor guy is hurrying to work so he doesn’t get fired or rushing home to a wife in labor. Experiment with what relaxes you, as there’s no one-size-fits-all remedy. Find whatever refocuses your attention and spend time on it.

Use your mind to tell your body how to relax, as Dr. J.H. Schultz taught in the 1940s. Repeat these phrases several times: “My stomach is warm.” “My forehead is cool.” “My breathing is relaxed and effortless.” “My heartbeat is slow and regular.” And then, “I’m at a peace and I’m relaxing.” These all are opposite of how your body feels when you’re anxious, as when the fight-or-flight response sends blood to the extremities. Waitley says Schultz discovered that simply by saying, for example, “My left arm is heavy and warm,” instructs the body what it should be feeling.

Tips for living longer: “If you make five—just five—adjustments to your life, you can have a dramatic effect on your life expectancy and the quality of your life,” Roizen and Oz write in You: The Owner’s Manual. The five things: control stress, control your blood pressure, don’t smoke, exercise 30 minutes daily and eat healthy. Do these five things and “in the next 10 years you will have just a 10 percent chance of dying or having to suffer disability compared to a typical person your age. We’ll take that bet.”

Why Getting Enough Sleep Is Critical
Some surprises about sleep: Most weight-loss diets won’t work well if you’re sleep-deprived, says sleep specialist and clinical psychologist Michael Breus. You may be exercising religiously, doing exactly what you’re supposed to do, but still not lose weight because of lack of sleep. Another thing: Not getting enough REM sleep sometimes may explain certain types of memory issues, like when you walk into a room and forget why you’re there.

It’s pretty rare that people need eight hours of sleep, Breus says. A better number is 7.5 hours (which provides five full sleep cycles of 90 minutes each; it’s toward the end of those cycles that the brain gets benefits). Some people may actually feel best after six hours or even nine. But whatever your individual needs, not getting enough sleep impacts your metabolism. Food won’t be digested appropriately.

Roizen says lack of sleep also inhibits your body’s ability to make growth hormone, and that impairs the growth and recovery of cells.

If you routinely suffer the worst sleep, you may feel three years older than your actual age, says Roizen, who has done extensive research into factors contributing to aging, which he’s published on his RealAge.com site. If you consistently get the best sleep, you could feel three years younger.

Tips for a good night: A pillow turns out to be a critical factor in how well you sleep, so one of the easiest things you can do is get a new pillow, which should be replaced every 18 months (some need replacement every year), Breus says. If you sleep on your side, choose a pillow that’s thicker. If you sleep on your back, get a thinner pillow.

Count backward from 300 by threes. “It sounds crazy but it works,” Breus says. “You can’t think of anything else, but it’s so doggone boring, so you’re out like a light.”

Switch to decaf drinks by 2 p.m. daily. Caffeine can stay in your system up to 12 hours.

Tips for snorers—and suffering spouses: Snoring isn’t only annoying; it could be a sign of other issues like sleep apnea, especially for snorers who are overweight, which is associated with an increased risk of cardiovascular disease, stroke, high blood pressure, arrhythmias, diabetes and sleep-deprived driving accidents. But there are treatments, most commonly involving use of the continuous positive airway or CPAP device. Talk to your doctor.

Tip for bedtime: Set an alarm clock to ring for bedtime, Breus says. If you must awake at 6:30 a.m., count back eight hours. Set the bedtime alarm for 10:30 p.m. That allows time to get ready for bed and get 7.5 hours of sleep. Otherwise, people tend to get on the computer at night or watch TV, then look up at the clock and see it’s late. “They don’t know where those hours went,” Breus says.