🎂 The Anti-Aging Effects of Happiness
The science connecting positive moods to a healthier life
The idea that “happiness is good for you” might sound like a truism, but it raises some complicated questions. It’s not necessarily the case that happiness has to be good for your health; it could simply be a pleasant feeling with no other significant impact. Why should smiling translate into a stronger immune system or longer life?
To understand whether a good mood generally enhances physical health over the years, you need to find scientific experiments that connect concrete happiness outcomes to concrete health outcomes. Neither is particularly straightforward to measure, so compelling research on this topic is pretty scarce. But since 2020, efforts have started to pick up. I’ll focus on two specific questions here:
Is happiness associated with less age-related memory decline?
Can actively boosting happiness improve health outcomes?
🐢 Happiness is linked to slower memory decline
In a study published in 2020, Emily Hittner and her academic colleagues analyzed data from an 18-year longitudinal study that started in the mid-1990s and ended in the mid-2010s (most participants in the study were aged 40-60). At three timepoints, each separated by nine years, the researchers collected data on people’s “positive affect”, which basically means their levels of good mood. Referring to the last 30 days of their life, people had to report how much they had experienced feelings such as “enthusiastic”, “cheerful”, “calm and peaceful”, and “in good spirits”.
At the second and third timepoints, researchers also collected data on memory performance. This involved a telephone-based test in which people had to listen to a list of 15 unrelated words and then recall as many as possible within 90 seconds.
The data first confirmed two simple patterns:
As expected, memory declines with age.
Positive affect (happiness) increases with age.
The second pattern is only true because the participant sample mostly contained middle-aged and older people. When you include younger people, evidence suggests there’s a U-shaped function for happiness. Across countries around the world, people generally have high happiness in young adulthood, but it then dips into the 40-50 age range before rising again in the 60+ age range (my schematic visual below shows how this pattern typically looks in the US).
In addition to confirming these pre-existing insights about how happiness and memory interact with age, Hittner and her colleagues checked whether levels of happiness moderated how much memory declined with age.
They found that people who reported feeling happier in the middle of the 18-year study showed less memory decline nine years later at the end of the study. Regardless of people’s demographics or how good their memories were overall, lower happiness was consistently linked to a steeper loss of memory over time. When the researchers checked the reverse association—whether memory performance in the middle of the study predicted happiness nine years later—they found no effect. It’s therefore unlikely that the connection was caused by weak memories making people unhappy.
So the data hint that happiness may protect against memory decline with age. But the study is purely observational in the sense that it relies on measuring people’s natural trajectories over time. To really understand whether happiness can cause changes in broader psychological and physical health, you need an intervention study that manipulates people’s happiness levels and measures health outcomes.
📈 Boost happiness to boost health
Another study in 2020 recruited 155 adults and randomly assigned half of them to receive a happiness treatment. The treatment was a 12-week program of activities designed to boost happiness, and each week, the researchers asked participants to rate their physical health using questions from the Behavioral Risk Factor Surveillance System used by the CDC. In addition, they assessed people’s general moods and life satisfaction.
I’ve listed the ten happiness treatment activities in the visual map below, grouping them into what I consider to be similar themes.
People who received the happiness treatment reported experiencing more positive emotions and fewer negative emotions over the course of the treatment along with greater life satisfaction. In contrast, the control group who received no treatment showed none of the same signs of progress.
So the happiness treatment successfully boosted happiness, but did it improve physical health too? By the end of the course, treatment participants were ~20% more likely than control participants to have a day in which they “felt healthy and full of energy”. They were also less likely to report a sick day, with an incidence rate roughly a third lower than the control group’s.
The picture isn’t yet complete because the study used only a passive control group. A stronger study in the future would need to compare the happiness intervention to some kind of placebo intervention to see whether it performs just as well when participants in both groups expect to see a benefit. The researchers also failed to find reliable biological markers underlying people’s self-reported health improvements (although they only measured blood pressure and body mass index).
In other words, it’s sensible to remain cautious in interpreting how happiness impacts physical health as more research emerges over the coming years. But there’s plenty of reason to be optimistic in believing that each smile on your face helps to support a healthier biology. So feel free to investigate whether happiness-boosting activities impact your own fitness.
And of course, even if you don’t notice a health improvement, at least you’ll be happier.
⭐️ Takeaway tips
Happiness is good for your health: Although not yet conclusive, there’s good data supporting the idea that happiness improves feelings of life satisfaction and also supports a healthier body. Our mental health is just as important as our physical health, and since the two are inextricably linked, we shouldn’t treat them as isolated constructs. Actively working to improve both domains is the most efficient route to a longer, healthier, and more joyful life.
Happiness and stress have a U-shaped function with age: Happiness seems to be higher at younger and older ages and lower in the middle around your 40s. Stress shows the opposite U-shaped pattern—lower at younger and older ages with a high point in the middle around your 30s. Keep these average patterns in mind when interpreting your life. It’s normal to feel alone during your low points but we all have a lot in common.
Boost your happiness with targeted interventions: Happiness isn’t entirely outside our control. At times, it feels ephemeral and driven by chance occurrences, and some people have a harder time finding it than others. But it’s also something we can actively reinforce with concentrated effort. Try out the ten evidence-based happiness activities I listed earlier in my visual map. You can select a couple of activities from the chart each day and do your best to apply them when you get the chance. Pay attention to how you feel as you use them and slowly build yourself a routine that’s optimized for your own happiness.
💡 A final quote
“Those who do not observe the movements of their own minds must of necessity be unhappy.”
~ Marcus Aurelius
❤️ If you enjoyed this, please share it with a few friends. If you’re new here, sign up below or visit erman.substack.com
📬 I love to hear from readers. Reach out any time with comments or questions.
👋 Until next time,
Erman Misirlisoy, PhD