There are two types of people in this world: those who swoop up their accidentally dropped keys with no complaints and go along their merry way and those who, more often than not, can't pick them up without cursing or letting out a big, miserable sigh.

An insignificant occurrence, yes, but it's often the mundane incidents (a whining child, an on-the-fritz printer) that reveal how vastly different human temperaments can be, says Michael D. Robinson, Ph.D., a professor of psychology at North Dakota State University.Some people take life's small slights and setbacks with a shrug, while others freak out, blow up, or fly off the proverbial handle in a loud huff or with silent seething. Why such a yawning gap in behavior? This is a question that scientists have only recently recognized as being significant to health.Just as life's most challenging experiences can flood the bloodstream with stress hormones, the smallest hassles can take a toll as well, says Nancy Nicolson, Ph.D., an associate professor of psychiatry and psychology at Maastricht University in the Netherlands."The changes are small -- a 10 to 15% increase in cortisol levels in response to typical daily annoyances, as opposed to a 100 percent or more increase during very stressful events," like a college entrance exam. But these small fluctuations "happen more frequently and can have a cumulative effect," says Nicolson.Feeling chronically stressed increases the risk of heart disease and weakens the immune system. It can also compromise some types of memory and learning, says Carmen Sandi, Ph.D., the director of the Brain Mind Institute at the École Polytechnique Fédérale de Lausanne in Switzerland. If we could all be more even-keeled (so we didn't sweat the small stuff), we would enhance our physical and mental health.Recent research suggests that we can train ourselves to not sweat the small stuff. To be a more even-keeled person, first you need to think like one, says Rosalind S. Dorlen, Psy.D., a clinical psychologist in New Jersey. That means using mental strategies that exercise the region of the brain that's responsible for reasoning, so that it isn't overwhelmed by the part of the brain that's involved in emoting. To do that takes practice. Consider every irritating incident as a chance to work out the reasoning area in your brain and you'll realize that what constitutes a stressor is subjective and that little set-backs will ruin your day only if you let them.Real Simple presented a few everyday nuisances to experts in the field of emotional regulation and asked, "What would an even-keeled person do?" Here are their answers.You feel: InconveniencedThe situation: You put off your errands. You canceled your lunch date. All so you could be home for the cable guy between 9 a.m. and 1 p.m. He never shows up.How to stay calm: Reframe the circumstances. "Thinking differently calms down your brain's emotional region," says James Gross, Ph.D., a professor of psychology at Stanford University. For instance, if you spent your morning lingering over coffee and the paper while waiting, try to view this as a rare, unexpected luxury instead of a waste of time.It's also helpful to think of the big picture. As Dorlen puts it: "What's going on and how you end up feeling depend on where you point the lens." Perhaps the cable guy simply had more assignments than he could humanly keep up with. This is not to say that you should let it go. You absolutely should call the cable company and express your frustration. But by readjusting your perspective, you can voice your displeasure in a less angry way and still get results.You feel: DefeatedThe situation: You've prepared for a presentation for weeks, but you end up blanking on key points. Back at your desk, you're about to break down in tears as you replay the episode in your head over and over again.How to stay calm: Focus on the present. After all, "it's never the stress-inducing event that you're freaking out about," says Steven Berglas, Ph.D., a life coach in Los Angeles. "It's what you're afraid might happen because of it," whether that's being reprimanded by your boss or laughed at by your colleagues.But that's not real at the moment; what's real is that you can take control of the situation. Quell the angst with an impromptu meditation session. Rick Hanson, Ph.D., a clinical psychologist in San Francisco and the author of Hardwiring Happiness, suggests quietly taking a moment to breathe in and two slow moments to breathe out. "Inhaling speeds up the heart rate," he says, "and exhaling slows it down."At the same time, say to yourself what you feel (I am upset), then let that label disappear from view. "Naming your emotions as you're feeling them reduces the activation of your emotional brain and engages your reasoning brain," says Hanson. Now you can focus on fixing the problem, which could be as simple as sending out a recap memo on your presentation that includes a summary and the points that you missed.You feel: AnxiousThe situation: Your husband is running late (though he swore he would be on time). Now you're going to be late for your appointment, and your toddler just wiped his nose on your skirt.How to stay calm: Problem-solve. If even-keeled people rarely appear stressed, it's because they're too busy looking for answers. A tardy spouse and a soiled skirt aren't catastrophes to be cursed at but circumstances to be fixed. Dorlen suggests asking yourself, immediately after the offending incident happens, How am I going to solve this?"Once you phrase the question in your mind, you have awakened the reasoning portion of your brain and put yourself in a position to find an answer," says Dorlen, the clinical psychologist. "You're no longer the victim of your emotions." Next, pretend that you're a coach with a game plan, such as pulling on a clean skirt, taking your child with you, and texting your husband to meet you at your appointment. Now take action.You feel: DisrespectedThe situation: Somehow, your offer to bring back coffee for an office mate has turned into an order for six complicated lattes. As you rattle off the list to the barista, you notice that she is rolling her eyes.How to stay calm: Speak positively. To understand why this is important, it helps to know a little brain anatomy. The brain is made up of cognitive and emotional parts, and the emotional part is composed of various circuits, says Andrew Newberg, M.D., director of research in integrative medicine at Thomas Jefferson University Hospital, in Philadelphia.These circuits include the reward system, which reinforces positive experiences, and the sympathetic nervous system, which connects the brain to the body and issues a fight-or-flight response when you feel stressed. Positive words (which we grew up associating with something pleasant, such as caring teachers) activate the reward system. Negative words (which we associate with something unpleasant, like playground bullies) spike angry or sad thoughts.So, if you're not willing to let it go, say, with a good-natured laugh, "I know this long order is annoying. I wish I had a shorter list, too," as opposed to "Hey, you're rude!" The words will calm you, and they will also put the other person in a more generous frame of mind. "Our emotional states reflect those around us," says Newberg. If you speak pleasant words in a calm tone, chances are, the other person will reply with pleasant words in a calm tone. Starting the exchange in a peaceful way increases the chance that you'll be sipping on your espresso sooner rather than later.You feel: DisappointedThe situation: You've been planning this cocktail party for weeks. Now that the big day is here, it's snowing. Heavily.How to stay calm: Embrace optimism. "Behind every setback, there's an expectation that things should be different," says Dorlen.Even-keeled people are no different, but when things don't go as planned, they feel hopeful that circumstances will get better. Which in this case may mean thinking, "with fewer people, our gathering will be much more intimate and relaxed. And who doesn't love that on a cold winter's night?""Optimism buffers the effects of stress—not only for everyday hassles but also for life-altering challenges," says Madelon Peters, Ph.D., a professor of experimental health psychology at Maastricht University. Optimism is also associated with resilience. That's why optimists are better able to bounce back after difficult times.While it's tough for natural-born pessimists to don rose-colored glasses instantly, they can condition their brains so that it gets easier to do so over time. In a 2011 study published in the Journal of Behavior Therapy and Experimental Psychiatry, women who participated for two weeks in an imagery and writing exercise in which they imagined an optimal future reported a sustained increase in optimism compared with those who wrote about random topics.To try this technique, imagine yourself 10 years from now under the best possible, yet still realistic, circumstances. Write down specific details. (Where do you live? What do you love about your life?) Then spend five minutes each day visualizing these details. "Imagery can create vivid and, in this case, positive emotional responses. These images and associated emotions end up living in your memory almost as if they were real," says Peters. In the short term, compared with the world created in your mind, the once unbelievably aggravating everyday letdowns may become small and surmountable.The biology of chillAnyone can become more even-keeled using the mental strategies on these pages, but naturally irascible personalities might need to put in a little extra effort. Temperament, after all, is partly genetic. Think of the brain as a seesaw: On one side are the frontal lobes, the region associated with reasoning; on the opposite side is the amygdala, where emotions, both good and bad, are generated. In between, where the imaginary fulcrum sits, is the anterior cingulate, which mediates the opposing forces.In each person, one side is inherently more influential than the other, explains neuro-scientist Andrew Newberg, M.D. What results is a person's temperament (an internal balance or emotional tone), which can shift further to one side or the other depending on external forces. These forces can be traumatic (a divorce), annoying (traffic), or health-related (poor-quality sleep, inadequate nutrition—both of which can trigger chemical changes that compromise brain activity).For a hotheaded type, whose brain already seesaws toward the emotional side, negative events can exacerbate imbalance. For an even-keeled personality, the brain may tip over to the emotional side only ever so slightly. No matter which group you fall into, just a small push toward the reasoning area of the brain can mean the difference between a run-in with a colleague that ruins your entire weekend and one that you can leave at the office without a second thought.(CNN)ANN.Az