Writer John Leonard had it right when he said, "It takes a long time to grow an old friend."

Simply put, old friends know us well and like us anyway. We need friends to get us out of the house, to listen when life gets rough and to help us find joy in each day. And, as it turns out, friends can even keep us healthy.

In a recent finding, The National Academy of Sciences notes how being isolated socially can be very harmful. Specifically, "Social isolation increased the risk of inflammation by the same magnitude as physical inactivity during adolescence, and the effect of social isolation on hypertension exceeded that of clinical risk factors such as diabetes in old age." Who knew?

Some friendships fall by the wayside, but some can survive even if it has been years since we have seen or heard from a person. And just as it is with dating, sometimes you have to make the first move to rekindle a friendship flame.

Today's seniors have kept in touch by letter and phone calls -- or met up at school reunions -- but thanks to social networks, more older individuals are catching up with one another after decades of being apart. Remember, however, that being friends on Facebook isn't the same as spending time with that friend in person.

Marlene Mulford knows it takes some effort to keep good friendships going. She is now in her late 60s, retired and spending more free time with the people she cherishes, including her high school classmates.

"I've been blessed with lifelong dear friends, some as far back as grade school. There wasn't always the opportunity to get together through the years due to distance, family and careers. With the help of Facebook and Messenger, I've joined a group of high school friends who have reconnected since retirement," Mulford says.

"Just recently I had a 'bunking party' -- an older term for 'sleepover.' Seven girlfriends traveled (across state lines) for a weekend at my house," she says. "With pillows, overnight bags and the gift of friendship, we spent time together in endless conversation, laughter, shopping and dining out. The evening ended a bit earlier than it would have 50 years ago. We all agreed it was an incredible time and we vowed to repeat this event annually, with get-togethers in between."

About once a year, Barb Tschacher, 65, travels across the country to see her family and meet up with her childhood friends. Sadly, one of her best friends passed away a few years ago, but that only makes her appreciate her other long-time friends even more.

"My remaining best friend from childhood, Mary, and I keep in touch through phone calls and text messages throughout the year, especially on birthdays and Christmas," she says, adding that they've been together through both happy and very sad life events. "You know, Mary is one of those people who can talk to anyone and people are comfortable around her. She has always been like that and that is one of the best things about her."

Even when life gets tough, maintaining close relationships with others is the best way to get through it. And as the research proves, what warms our hearts -- love, laughter, reminiscing -- is also healthy for our hearts.

"I always look forward to visiting with all my friends from my childhood when I go home -- to catch up on what is new in their lives, look at pictures of their grown kids and any grandchildren," says Tschacher. "We laugh so much. It's really true. Old friends are the best friends!"