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Why Feeling Happy Can Make You Feel Healthy

... and decrease feelings of sickness.

Key points

  • A study that manipulated people's happiness with an intervention revealed that happiness and health are positively related.
  • In the study, increasing people's happiness both increased feelings of health and decreased feelings of sickness.
  • Increasing people's happiness, however, did not affect objective measures of health according to the study in a 3-month period.
iStock image by pixelfit licensed to Art Markman
Source: iStock image by pixelfit licensed to Art Markman

There is a lot of evidence that happiness and health are linked. In general, people who are happy are also healthier than those who are not happy. The problem is that it is hard to know whether being happy leads to better health. Perhaps people who are unhealthy have a harder time being happy than those who are healthy. Perhaps people who are healthy engage in more behaviors that lead to good long-term health. Perhaps being happy makes you feel healthier.

Research on Health and Happiness

To explore some kind of causal relationship between health and happiness, it is important to find a way to manipulate people’s happiness so that it can be studied experimentally. That approach is the one taken in a paper in a 2020 issue of Psychological Science by Kostadin Kushlev, Samantha Heintzelman, Lesley Lutes, Derrick Wirtz, Jacqueline Kanippayoor, Damian Leitner, and Ed Diener.

These researchers tested a group of 155 adults. Half were given a 12-week positive psychology intervention that taught a variety of techniques that help improve people’s happiness including mindfulness meditation, gratitude, and developing better social relationships. The other half were in a wait-list control in which they were told they would be getting the happiness intervention later, but did all of the measures at the same time as the individuals who went through the training.

During the training, the researchers measured people’s judgments of happiness as well as measures of how healthy they were feeling. They also took some measures of physical health including blood pressure and body mass index (BMI). These subjective and objective measures of health were also taken three months after the positive psychology intervention was completed.


The intervention worked as expected. By the end of the program, the happiness of the people who went through the intervention increased significantly, but the happiness of the people in the wait-list control did not change substantially.

Both by the end of the program and three months later, the people who went through the intervention felt healthier and experienced less sickness than those in the control condition. In addition, as the program was going on, week-by-week increases in happiness led to increases in feelings of health and decreases in feelings of sickness.

Interestingly, the positive psychology intervention did not influence any of the measures of physical health. That is, blood pressure and BMI did not differ between the groups.

This pattern of results suggests that (at least over a six-month period) instilling a higher level of happiness causes people to feel healthier and to experience less feeling of sickness compared to people who did not go through an intervention aimed to increase happiness.

What is less clear from these findings is exactly how increases in happiness change the experience of health. At least over this time period, happiness does not change basic objective markers of health. It might just make people feel better so that they do not experience feelings of sickness. It is possible that happiness influences the ability of the body to fight disease.

It is also possible that the long-term effects of happiness on health might have a different cause. For example, happier people might be more willing than unhappier people to engage in healthy behaviors like eating well or exercising or may engage in fewer self-destructive behaviors like excessive drinking or smoking.

Finally, it would be interesting to see whether long-term differences in manipulated happiness influence physiological markers of health in addition to subjective judgments of health. It may be that the study period was just too short to see physiological changes or that other mechanisms kick in when people are happy over a longer period of time. It would also be useful to see whether manipulations that increase happiness also lead to more behaviors that are healthy for the long term.

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Kushlev K, Heintzelman SJ, Lutes LD, et al. Does Happiness Improve Health? Evidence From a Randomized Controlled Trial. Psychological Science. 2020;31(7):807-821.