What makes a good life? A Harvard study that spanned 75 years using data from multiple generations of researches found the answer.

This incredible feat tracked the physical and emotional well-being of two groups: 456 poor men growing up in Boston from 1939 to 2014 (the Grant Study) and 268 men who graduated from Harvard’s classes of 1939-1944 (the Glueck study). Since before World War II, the research teams conducted and extensive analysis.

Here’s what they discovered: good relationships are key to happiness and health. Overall people who fared the best in life were the ones who leaned in to relationships. People who are more socially connected to family, friends and community are happier and physically healthier.

On the flip side, the experience of loneliness is so toxic that health declines earlier in life and results in a shorter life with faster declining brain function.

Those happiest in retirement were the ones who replaced their workmates with friends.

For many of us, we intuitively know these facts to be true, yet it can be difficult to implement because relationships are often complicated and cultivating family and friends can often feel relentless and hard.

Here are some pointers to keep you on the path of living a quality life:

>> Go for quality not quantity. It’s not the number of friends nor is it being in a committed relationship that is an indicator of happiness and health. It’s the quality of relationships that matters completely. People who are the most satisfied in their relationships in their 50s are the healthiest in their 80s. Good relationships protect our bodies and brains.

>> Replace screen time with people time. Your relationship with the television, computer or mobile devices are chipping away at your time to create interpersonal connections. “Liking” a photo of a friend on social media is not a substitute for being a face in that photo, nor does offering an emoji indicate as an exchange of authentic emotion.

>> Expand and enliven your routine. Liven up what’s become mundane in your relationships. Schedule date nights, gatherings and create opportunities that are out of the ordinary for you. It could be watching the sunset with someone on the beach, going to the movies or finding something new to try.

>> Live in the present. There is no such thing as a family that hasn’t been challenged by conflict. Find ways to mend bridges, see the benefit of having those that challenge you in your life and re-establish relationships with boundaries that you can live with.

Mark Twain once wrote: “There isn’t time, so brief is life, for bickering, apologies, heart burnings, callings to account. There is only time for loving, and but an instant, so to speak, for that.”

Alice Inoue is the founder of Happiness U. Visit yourhappinessu.com.