This 75 year study provides clarification really of what we probably already know, that happiness offers a sustaining system for the body and mind, alleviating physical pain, leading to greater life expectancy and in relationships bickering is ok, as long as you actually have a relationship with someone you feel loved and can count on.
" Once we had followed our men all the way into their 80s, we wanted to look back at them at midlife and to see if we could predict who was going to grow into a happy, healthy octogenarian and who wasn't.And when we gathered together everything we knew about them at age 50, it wasn't their middle age cholesterol levels that predicted how they were going to grow old. It was how satisfied they were in their relationships.
The people who were the most satisfied in their relationships at age 50 were the healthiest at age 80. And good, close relationships seem to buffer us from some of the slings and arrows of getting old. Our most happily partnered men and women reported, in their 80s, that on the days when they had more physical pain, their mood stayed just as happy. But the people who were in unhappy relationships,on the days when they reported more physical pain, it was magnified by more emotional pain.
And the third big lesson that we learned about relationships and our health is that good relationships don't just protect our bodies, they protect our brains. It turns out that being in a securely attached relationship to another person in your 80s is protective, that the people who are in relationships where they really feel they can count on the other person in times of need, those people's memories stay sharper longer. And the people in relationships where they feel they really can't count on the other one,those are the people who experience earlier memory decline. And those good relationships, they don't have to be smooth all the time. Some of our octogenarian couples could bicker with each other day in and day out, but as long as they felt that they could really count on the other when the going got tough,those arguments didn't take a toll on their memories."
The information stems from this study by Grant And Glueck http://www.adultdevelopmentstudy.org/grantandglueckstudy