One of the best things you can do for your long-term health is to spend time with people who you care about.
An 80-year study of more than 250 men, which started when they were sophomores at Harvard during the Great Depression, suggested that close, nurturing relationships were more important for their long-lasting happiness than wealth, intelligence, or genetics.
"Good relationships don't just protect our bodies; they protect our brains," study director Robert Waldinger said in a TED talk.
Another study of more than 300,000 people around the globe found that people with "adequate social relationships" are 50% less likely to die. Being with a partner can help, too. Researchers have long noticed that married people are better nourished and survive more heart attacks. Married men specifically tend to have better brain health in old age.
Conversely, people who feel more isolated and lonely fare worse when it comes to a host of health outcomes: They develop higher rates of heart problems, obesity, and cognitive decline. In fact, one study of more than 1,600 people in the US over age 60 found that loneliness was predictive of both functional decline and death. (But it's important to remember that loneliness isn't the same thing as being alone, so it's best to focus on the quality of your relationships, instead of how much time you spend around other people.)