Protect your DNA As we age, the ends of our chromosomes -- called telomeres -- become shorter. This makes people more vulnerable to disease. You might think there's nothing you can do, but new research suggests otherwise. In a pilot study, lifestyle changes boosted an enzyme that increases telomere length. Other studies also find diet and exercise can protect telomeres. So healthy habits may slow aging at the cellular level. Be conscientious An 80-year study found one of the best predictors of a long life is a conscientious personality. Researchers measured attributes like attention to detail and persistence. They found that conscientious people do more things to protect their health and make choices that lead to stronger relationships and better careers. Make friends Science has given you one more reason to be grateful for your friends – they might help you live longer. Australian researchers found elderly social butterflies were less likely to die over a 10-year period compared to people with the fewest friends. Another analysis of results from 148 studies supports the link between plentiful social connections and longevity. Choose your friends wisely Your friends’ habits rub off on you, so look for companions with healthy lifestyles. Studies indicate obesity is socially “contagious" – your chance of becoming obese increases by 57% if you have a friend who becomes obese. Smoking is another habit that spreads through social ties, but the good news is that quitting is also contagious. Quit smoking While it's no secret that giving up cigarettes can lengthen your days -- the amount of extra time may surprise you. According to a 50-year British study, quitting at age 30 could increase your lifespan by an entire decade. Kicking the habit at age 40, 50, or 60 boosts life expectancy by 9, 6, or 3 years, respectively. Embrace the Siesta A siesta is standard in many parts of the world, and now there's scientific evidence that napping may help you live longer. A recent study with 24,000 participants suggests that regular nappers are 37% less likely to die from heart disease than occasional nappers. Researchers think naps might help your heart by keeping stress hormones down. Follow a Mediterranean diet The Mediterranean diet is high in fruits, vegetables, whole grains, olive oil, and fish. An analysis of 50 studies involving more than half a million people shows the impressive benefits of this diet. The findings show it significantly lowers the risk of metabolic syndrome – a combination of obesity, elevated blood sugar, increased blood pressure, and other factors that raise your risk of heart disease and diabetes. Eat like an Okinawan The people of Okinawa, Japan once had the longest life expectancy in the world. Researchers attribute this to the region's traditional diet, which is high in green and yellow vegetables and low in calories. Some Okinawans make a habit of eating only 80% of the food on their plate. As younger generations have veered from these traditions, life expectancy in Okinawa has fallen. Get married Several studies show that married people tend to outlive their single counterparts. Many researchers attribute the difference to the social and economic support marriage provides. While a current marriage offers the greatest benefit, people who are divorced or widowed have lower mortality rates than those who have never been married. Lose weight If you're overweight, slimming down can protect against diabetes, heart disease, and other life-shortening conditions. Belly fat appears to be particularly harmful, so focus on deflating that spare tire. A 5-year study of Hispanics and African-Americans suggests eating more fiber and exercising regularly are effective ways to reduce belly fat. Keep moving The evidence is overwhelming – people who exercise live longer on average than those who don't. According to dozens of studies, regular physical activity reduces the risk of heart disease, stroke, diabetes, some forms of cancer, and depression. Exercise may even help you stay mentally sharp in your old age. Ten-minute spurts of activity are fine, as long as they add up to about 2.5 hours of moderate exercise per week. Drink in moderation Heart disease is less common in moderate drinkers than in people who don't drink at all. But keep in mind that too much alcohol pads the belly, boosts blood pressure, and can cause a host of other health problems. The American Heart Association recommends that if you drink alcohol, the limit should be one drink a day for women and one or two for men. But if you don't drink, don't start. There are many other ways of protecting your heart. Get spiritual Research suggests people who attend religious services tend to live longer than people who never attend. In a 12-year study of people over age 65, those who attended services more than once a week had higher levels of a key immune system protein than their peers who attended no services. They were also significantly less likely to die during the study period. The strong social network that develops among people who worship together may contribute to their overall health. Forgive Letting go of grudges has surprising physical health benefits. Chronic anger is linked to decreased lung function, heart disease, stroke, and other ailments. Forgiveness will reduce anxiety, lower your blood pressure, and help you to breathe more easily. These benefits tend to increase as you get older. Use safety gear Accidents are the fifth most common cause of death in the U.S., and the top cause of death for people ages 1 to 24. Wearing safety gear is a simple way to boost your odds of a long life. In the event of a motor vehicle crash, seatbelts reduce the risk of death or serious injury by 50%. In bike accidents, most deaths are caused by head injuries, so always wear your helmet. Make sleep a priority Getting enough good quality sleep can lower the risk of obesity, diabetes, heart disease, and mood disorders. Sufficient sleep will also help you recover from illness faster. Burning the midnight oil, on the other hand, carries serious health risks. Sleeping less than 5 hours per night boosts the risk of premature death, so make sleep a priority. Manage stress Dean Ornish, MD, has published research suggesting that lifestyle changes including stress management not only help prevent heart disease, but may actually reverse it. Although avoiding stress is not a viable option for most people, there are effective ways to control it. Try yoga, meditation, or deep breathing. Even a few minutes a day can make a difference. Maintain a sense of purpose Finding hobbies and activities that have meaning for you may contribute to a long life. Japanese researchers found men with a strong sense of purpose were less likely to die from stroke, heart disease, or other causes over a 13-year period compared to those with a low sense of purpose. Another study at Rush University Medical Center indicates that having a greater sense of purpose is linked to a reduced risk of Alzheimer’s disease.