In the time you spend reading this article, you could instead take a walk and just maybe be happier.

Robert Roy Britt

Jan 28, 2019·8 min read

Whether and how exercise fuels happiness has been the subject of much research with few solid conclusions. But the evidence is getting much stronger, as more and more findings tie physical activity to happiness, even if they often leave open the question of which causes which.

The case is bolstered by a new study that provides some of the strongest objective evidence yet that exercise can thwart depression—arguably the inverse of happiness, or at least an obstacle on the road to mental wellbeing.

Importantly, it doesn’t seem to take much time to improve your mood, if the exercise-causes-happiness claims are directionally correct. Taking the stairs at work, sweeping out the garage or tending to your garden, in combination with other physical activity, appears to sow some seeds of happiness, a recent review of nearly two dozen studies found.

“The link between exercise and mood is pretty strong,” says Michael Otto, a professor of psychology at Boston University, speaking to the broad body of research. “Usually within five minutes after moderate exercise you get a mood-enhancement effect.”

Hmm. Let’s assume any lasting effects might take a little more effort. But hey, we have to start somewhere.

Prop 1: Exercise Fuels Happiness

Exercise, especially when vigorous, is known to release endorphins, hormones that generate positive feelings and even inhibit pain. This is why exercise is often recommended as one ingredient in a treatment recipe for many physical and mental ailments.

So just how much exercise is needed, and at what intensity, for the body to produce positive mood-altering effects on the brain? In setting the lowest likely bar, you can set aside the word “exercise.”

In a review last year of 23 peer-reviewed studies on physical activity and happiness, involving thousands of people from school children to seniors, University of Michigan researchers concluded that just about any activity is better than none, and more is better. Up to a point.

“Our findings suggest the physical activity frequency and volume are essential factors in the relationship between physical activity and happiness,” said study leader Weiyun Chen. “More importantly, even a small change of physical activity makes a difference in happiness.”

Writing in the Journal of Happiness Studies, the researchers used data from the various studies to calculate odds that an active person would be happier than an inactive person, based on three levels of activity among the study subjects:

• Active (but insufficiently): 20 percent
• Sufficiently active: 29 percent
• Very active: 52 percent

They also found that happiness levels were the same for those who exercised between 2.5 and 5 hours a week vs. those who exceeded 5 hours.

But since happiness can be incredibly difficult to define, I’d call these odds very interesting but not necessarily conclusive. Chen and colleagues acknowledge that more research is needed to prove whether exercise causes happiness, or if other factors are involved. As just one example, it could be that exercise makes us healthier (which is well established by science) and being healthier is what makes us happy.

Prop 2: Happiness Fuels Exercise

Not as much research has been done whether happiness is a key to motivating people to exercise. But one 2017 study published in the Annals of Behavioral Medicine certainly suggests as much.

Over 11 years, nearly 10,000 people over age 50 were asked about their frequency and intensity of physical activity, at work and otherwise. Those with higher psychological well-being (a proxy for happiness and optimism) at the start of the study had higher levels of physical activity over the next decade. Also, those who started out happy and active were more likely to stay active.

“Results from this study suggest that higher levels of psychological well-being may precede increased physical activity,” said Julia Boehm, a researcher at Chapman University and lead author of the study.

In very preliminary results of my Happiness Survey for The Happiness Quest, regular exercise is emerging as a theme among those who self-report as being the happiest. However, the survey is self-selecting, the numbers are as-yet small, and the happiest respondents also associate strongly with other traits and habits, so at best the responses are just another possible indicator of an association between exercise and happiness, not a cause-and-effect relationship, and no indication in which direction any effect may flow.

[Taking the survey will help me better understand who is happy (or unhappy) and why. It’s totally anonymous.]

And: Exercise Battles Depression

On the flip side of the happiness question, several studies have found that exercise, even in moderation, can combat depression. While lack of depression may not be the definition of happiness, it’s certainly a good starting point, as I argued in another article. And this is where research has long shown a strong correlation—one that just got stronger.

Clear back in 2013, a review of 25 studies showed that even low levels of physical activity — such as walking or gardening for 20 to 30 minutes a day — can help battle depression for all age groups. (It must be noted: Maybe walking and gardening just bring joy or contentment irrespective of the movement involve. I mean, it’s nice to go for a walk or plant some arugula.)

Still, a study last year, reported in the journal Depression and Anxiety, found that “supervised aerobic exercise has large antidepressant treatment effects for patients with major depression.”

And much other research points to exercise as a way to reduce stress and anxiety, even suggesting that a 10-minute walk can be as effective as a 45-minute workout for this purpose, according to the Anxiety and Depression Association of America.

But many of these studies, before and since, have two problems:

• They often rely on some self-reporting, and people tend to prevaricate to make themselves look good or omit data (such as time spent gardening) they might not deem important on a questionnaire about physical activity.
• Question of causality nags researchers: Does physical activity remedy depression, or does depression lead to lack of desire to do something? And is depression the result of other factors, such as living conditions, relationships or job prospects, rather than lack of exercise?

Even More Convincing…

A new study involving data from thousands of individuals got past those concerns by drawing on two techniques:

• Accelerometers measured actual physical activity of test subjects, whether while jogging, climbing stairs at work or mowing the lawn. That’s objective data vs. unreliable self-reporting.
• DNA was probed for gene variants that, for example, are known to make a person more prone to exercise. The idea is this: If exercise alleviates depression, then people with those gene variants should be less depressed.

Taking these genetic factors into account, the researchers found “robust evidence” that “higher levels of physical activity reduce risk for depression.”

“On average, doing more physical activity appears to protect against developing depression,” said Massachusetts General Hospital researcher Karmel Choi, lead author of the study. “Any activity appears to be better than none; our rough calculations suggest that replacing sitting with 15 minutes of a heart-pumping activity like running, or with an hour of moderately vigorous activity, is enough to produce the average increase in accelerometer data that was linked to a lower depression risk.”

The findings are detailed in the Jan. 23, 2019 issue of the journal JAMA Psychiatry.

Exercise may not be a cure-all for those with severe, clinical depression, but it can be the ticket for others, says Michael Craig Miller, assistant professor of psychiatry at Harvard Medical School.

“For some people it works as well as antidepressants, although exercise alone isn’t enough for someone with severe depression,” Miller says. Acknowledging that it can be hard to get started, Miller suggests taking small steps. “Start with five minutes a day of walking or any activity you enjoy. Soon, five minutes of activity will become 10, and 10 will become 15.”

And Then There’s This and This and This …

There is a whole other body of work showing that exercise boosts memory and cognitive ability, particularly as we get older. And there is conclusive evidence that exercise improves overall physical health and lowers the risk of dying from many bad things. It also helps us sleep.

If you assume a sound mind and body and a good night’s sleep might bring some pleasure or at least contentment, it’s not a leap to suggest exercise contributes indirectly to happiness in many ways.

It’s important to note that happiness depends not just on factors we would hope to control, like taking a jog to release mood-enhancing endorphins, but health factors that may or may not be in our control, as well as the genes we’re stuck with. Also, some of the studies cited in this article considered fixed time frames and the possibly fleeting nature of happiness, not lifetime wellbeing.

What About You?

Given the many well-established benefits of exercise, does it really matter whether it directly creates happiness, or if a better mood comes as a byproduct of better physical wellbeing, or if none of this is true over the long run and a good workout simply makes you feel better for a little while?

For me, when any period of inactivity extends beyond a day or two, I begin a slide into a state of physical and mental molasses that gets deeper and thicker with time, until going for a hike or returning to the gym just seems an impossible slog. Dragging myself back out there erases the funk incredibly quickly, and that first sweat often triggers a physical smile of acknowledgement. I’m back. Why did I ever stop?

I can only conclude, despite the years-on, years-off nature of my exercise routine, that exercise puts me in a good mood. And when I’m in a good mood, I tend to exercise more. In many ways, it matters little which is the cause and which is the effect. And I’ll bet it’s simply a virtuous circle (and, in those off years, a vicious spiral).

But for now, I’m pretty happy to have finished this article, so I’m heading to the gym.

UPDATE Dec. 30, 2020: After a year of looking into happiness and well-being more broadly, and with the help of a survey, I know a little more now than I did on Jan. 1, 2019. The results are here.