Obsessing about your age.Does the thought of another birthday make you bristle? Believe us, you aren’t alone. But it’s best to check your attitude, because dwelling on it can have serious implications for the aging process. Fixating on the negative parts of getting older, like mental decline, could actually make you feel older, according to research from Purdue University. The good news? The secret to feeling younger is within your control: it’s as easy as believing that you are younger. (Need age-embracing inspiration? Check out what dozens of women have to say about the best parts of getting older.) A nut-free diet. Photo by Mitch Mandel Unless you’re allergic, you may want to add nuts to your snack rotation. Results from two long-term Harvard studies show that daily nut-eaters were less likely to die of cancer, heart disease, and respiratory disease—in a 30-year study follow-up they were found to be 20% less likely to die overall. Whether it’s walnuts, almonds, peanuts, pistachios, or another variety (preferably unsalted), a handful or two a day will do the trick. Acting stingy.Here’s one more reason that it’s better to give than receive: Altruistic acts could promote longevity. A study published in the American Journal of Public Health suggests that helping others reduces stress and, ultimately, lowers your risk of dying. Generosity really is the gift that keeps on giving. Sitting all day long.If you spend most of the day in the seated position, it’s time to take a stand. A study published in journal BMJOpen found that sitting for more than three hours a day can reduce life expectancy by two years. But what if you have a desk job? Do your best to get up periodically throughout the day to take a quick walk, get on your feet while you take phone calls, and see if your company can provide you with a standing desk. Every little bit helps. Staying up all night. Photo by Getty Images Whether you work the graveyard shift or just happen to hit your stride when the sun goes down, there’s a dark side to rising with the moon. Sleeping too little or consistently sleeping against your body’s biological clock raises your risk of type 2 diabetes, obesity, heart attack, and stroke, all to varying degrees. Less sleep is also thought to accelerate the brain’s aging process, according to research from Duke-NUS Graduate Medical School’s Center for Cognitive Neuroscience. And the list of reasons to catch more zzzs continues. (If you have trouble sleeping, these 20 simple tips can help.) Being down in the dumps.A lingering gloomy attitude isn’t just a bummer—it could also endanger your health. Women who are jealous, anxious, or moody and distressed in middle age may be at higher risk for developing Alzheimer’s later in life, according to a nearly 40-year study published by the American Academy of Neurology. The silver lining is that reducing your risk is as simple as working on your attitude. If you can’t get out of a funk yourself, consider talking to a therapist. Walking slowly. Photo by Getty Images Pounding the pavement at any pace is a great form of exercise, but a study of 39,000 walkers from the Lawrence Berkeley National Laboratory found that over a decade, the death rate was highest among the slowest strollers, even if they expended the same amount of energy as someone walking briskly for a shorter time period. You want to aim for 23 minutes per mile or faster to lower your mortality risk; use a pedometer on your next walk to pick up the pace. Living with sexual frustration. A study published in Biological Psychology found that people who recently had sexual intercourse had lower blood pressure than those who didn’t. And a study from the University of Michigan Health System suggests that sex could be one of the secrets to youth, well-being, and a longer life. In the study, male fruit flies that were exposed to the sexual pheromones of their female counterparts without the opportunity to mate experienced increased stress and ultimately lived shorter lives. Granted, this study was performed on fruit flies, so we can’t make any promises. But isn’t it worth a try? MORE: Remake Your Libido By Tonight