Researchers from Harvard University studied adult development, which is the longest-running analysis on adult happiness in the world. They tracked the lives of 700+ participants and 1,300+ descendants over 85 years. Here are 5 life lessons on happiness.

Lesson 1: Relationship Satisfaction Impacts Health

Relationship satisfaction was a more effective predictor of health at age 80 than cholesterol, blood pressure, or any other health marker tracked by the study.

The strength and quality of your relationships has a direct and powerful impact on your physical health as you age.

Lesson 2: Loneliness Kills (& It's More Prevalent Than Ever)

In 2023, the U.S. Surgeon General Vivek Murthy released a report, entitled Our Epidemic of Loneliness & Isolation, that sounded the alarm on a number of scary trends in society.

A few notable statistics:

• The amount of time teenagers are spending in person with their friends is down 70% over the last two decades.
• 60% of adults say they don't feel very connected to others.
• The number of men who say they have zero close friends is up 5x since 1990 (15% vs. 3%).

And unfortunately, loneliness kills.

A number of scientific studies—including Dr. Waldinger's Harvard Study—have found that the health impact of loneliness is quite dire.

Chronic loneliness has been found to increase dementia risk by up to 50%.

This image, cited in the Surgeon General's report, shows that a lack of social connection is worse for your health than tobacco and alcohol abuse, obesity, and more.

 

Lesson 3: Make "Social Fitness" a Priority

To fight back against loneliness, Dr. Waldinger suggests that we all need to make "social fitness" a priority.

His idea is that our social health should be thought of in the same manner as our physical health—that it's the result of tiny daily actions that compound over long periods of time.

This characterization resonates deeply—make your social health a part of your daily routines:

• When you think something nice about someone, let them know right then.
• Tell your partner one thing you appreciate about them every single day.
• Reach out to that friend and catch up.
• Plan that dinner or group gathering.
• Go on that trip with your old friends.

Your daily social health actions compound. Build your Social Fitness.

Lesson 4: Check Your Energy to Improve Your Life

When discussing strategies for improving relationship satisfaction and overall happiness, Dr. Waldinger offered an energy hack: After you consume a piece of content, assess your energy level. Did consuming that piece of content make you feel energized or drained?

If the latter, you may want to reduce the amount of that type of content that you consume.

I believe the same hack can apply to relationships: Check your energy level after spending time with someone. Do you feel energized or drained?

Spend more time with your energy creators and less time with your energy drainers. Your life will improve.

Lesson 5: Ambivalent Relationships are the Most Toxic

Ambivalent relationships—those that are sometimes supportive and sometimes demeaning—are actually worse for your health than purely demeaning relationships.

A variety of studies on humans and animals have shown that ambivalent relationships have sharper negative health consequences than purely toxic ones.

His explanation was that the relationships that are inconsistent leave a person exposed: They open up due to the love and support, allowing the demeaning behavior to cut deeper.

Audit your relationships. Consider those that may have ambivalent characteristics—people who are supportive at times, but deeply demeaning at others. It may be time to reduce the energy given to these people.

Relationships Are Everything

By far the biggest medical surprise of the past decade has been the extraordinary number of studies showing that the single biggest predictor of your psychological and physical health and wellbeing is simply the number and quality of close friendships you have.

Relationships are, quite literally, everything.

Invest in your relationships—they will pay dividends in all areas of your life for many years to come.

In summary, the 5 lessons from the conversation: (1) Relationship satisfaction impacts health, (2) Loneliness kills (and it's more prevalent than ever), (3) Make social fitness a priority, (4) Check your energy to improve your life, and (5) Ambivalent relationships are the most toxic.