- Longitudinal and experimental research suggests that happiness can promote better physical health.
- Physical illness can also impede happiness, particularly when it interferes with daily life.
- Researchers are still investigating for whom and under what conditions happiness may influence health (and vice versa).
What do you want most out of life? When asked this question, many people will say that they simply want to be happy and healthy. What these people might not know is that these two important life goals are intimately connected. Research suggests that happier people tend to live longer, experience fewer illness symptoms, and are less likely to develop diseases like heart disease and dementia. At the same time, physical illness can impede happiness, particularly when it interferes with daily life.
What is happiness?
Before we can understand how happiness is related to health, we need to define happiness. For some people, happiness might be feeling joy and excitement. For other people, happiness might be achieving personal goals or feeling connected to a community. Because happiness is a subjective experience, all of these definitions of happiness are valid. Similarly, psychological researchers have used many different definitions of happiness. In this post, I am going to focus on a particular definition of happiness—well-being—and how it is studied in the scientific literature.
One aspect of well-being, called subjective well-being, can be thought of as simply “feeling good.” A person experiences subjective well-being when they feel many positive emotions like joy and excitement, relatively fewer negative emotions like sadness and anger, and when they are generally satisfied with their lives. Another aspect of well-being, called psychological well-being, can be thought of as “living the good life.” A common model of psychological well-being is made up of six different components: purpose in life, personal growth, autonomy, self-acceptance, environmental mastery, and positive relationships with others. Together, subjective well-being and psychological well-being contribute to living a happy life.
How is happiness connected to health?
Researchers have found that higher well-being (i.e., happiness) is linked to better general health, less pain, reduced susceptibility to colds and flu viruses, and fewer chronic conditions such as heart disease and diabetes. Well-being can promote better physical health in a number of ways. First, when people feel good, they are more likely to engage in healthy behaviors such as exercising and eating well and they are less likely to engage in unhealthy behaviors such as smoking and substance use. Over time, these healthy habits can promote health and prevent disease.
Another way that well-being may promote health is by improving the functioning of the body’s physiological systems, such as cardiovascular and immune systems. When someone experiences stress, their body’s physiological systems react to protect them and to prepare them to respond to the stressor appropriately. However, when stress is chronic, these same physiological responses can damage health. Well-being may protect health by reducing experiences of stress and by improving people’s physiological responses to stress.
Is happiness the chicken or the egg?
Although many scientific studies have found that happier people tend to be healthier, researchers can’t yet say with certainty that happiness causes better physical health. Researchers would expect to see this same association if better physical health causes people to be happier, or if some other variable such as income or genetics causes both happiness and health. This is an important scientific concept: correlation does not equal causation. In other words, which comes first, happiness or health? Is happiness the chicken or the egg? Much like the chicken or the egg paradox, there is not a single, clear answer to this question.
Most research suggests that the connection between happiness and health is bidirectional. This means that greater well-being leads to better physical health, and better physical health leads to greater well-being.
The most common way that researchers investigate whether well-being leads to better health or vice versa is by using longitudinal studies. Longitudinal studies involve collecting data from the same individuals multiple times over several months, years, or decades. In a longitudinal study, researchers can measure well-being at one timepoint and test whether it predicts physical health outcomes much later in time.
Researchers can also use statistical methods to rule out other possible explanations that may link well-being to health in longitudinal studies, such as income or genetics. In general, this type of research design has found that well-being predicts better physical health decades later. For example, recent research conducted by myself and colleagues found that being happy, as well as becoming happier over time, predicted better physical health 4-18 years later.
Another way that researchers can investigate the causal effects of well-being on health is by using experiments. Experiments are a type of scientific study that allow researchers to draw causal conclusions. In an experiment, researchers manipulate one variable such as well-being and measure its effects on another variable such as physical health.
For example, researchers have manipulated well-being by randomly assigning one group of people to receive an intervention designed to boost well-being and randomly assigning another group of people to participate in a control condition. Researchers can then observe effects of the well-being intervention on health outcomes, such as health behaviors and biological indicators of health. These experimental studies have produced somewhat mixed results—in some studies, the interventions improved well-being and physical health outcomes, but in other studies these effects were not observed.
One of the challenges of these experimental studies is that researchers don’t yet know the best ways to intervene to improve well-being in the long term. Participants might experience a short-term boost in well-being, but sustained increases in well-being are likely necessary to influence health outcomes. Researchers also don’t know for whom and under what conditions interventions to improve well-being are most likely to influence health. For example, are experimentally induced improvements in well-being more likely to improve health in younger and healthier people? Or in older adults with chronic illnesses? Psychological researchers continue to explore these important open questions to develop a better understanding of the happiness-health connection.
In future posts, we will explore ways that individuals and societies may be able to increase happiness and improve health, psychological factors that may promote healthy aging and reduce dementia risk, and other scientific advances in our understanding of the happiness-health connection.
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