I remember a question I was asked a long time ago that puzzled me more than other really difficult ones. I had to describe a happy day and, rummaging through my bag of happy, interesting or downright glorious days, it wasn’t very clear to me what criteria I should use to choose one.

Happiness is a complicated thing, at least when you’re born with receptors sensitive to all the vibrations of pain around you. I felt, in turn and sometimes almost simultaneously, the guilt of not being happy enough and the guilt of being happy while other people’s lives seemed suffocating.

On days when there was no reasonable cause for cheerfulness, not even towards sunset, I have experienced a state of joy bordering on happiness—just as I have experienced days that were dull, even slightly gloomy, some of which seemed to me to be of unearthly happiness only later, when they were filed away in the drawer reserved for the most beautiful memories. I’ve sniffed at unfathomable happiness that would have required half a billion more alveoli in my lungs to inhale, and I’ve nibbled at small, everyday joys that are so tempting to dismiss into a pile of banalities.

Happiness is closely linked to our health and success, says researcher Sonja Lyubomirsky, pointing out that there is ample evidence that happy people are healthier, more creative, earn more money, are more productive, cope better with adversity and are more likely to get married.

To achieve greater happiness, we should first know what makes us happy. More time? More money? A life partner? Losing ten pounds? As desirable as achieving any of these goals might be, they would not increase our long-term happiness, at least not significantly, says Lyubomirsky.

Lyubomirsky’s research has shown that 50% of the factors that affect happiness are genetically determined, while circumstances account for 10% of our happiness. So if there were 100 people in a theatre at different points on a happiness continuum, even if we could turn them all into identical twins, they would still have different levels of happiness, just with the differences reduced to 50%.

On the other hand, what is really surprising is that if we put all 100 of them in the same circumstances (they would be equally beautiful or healthy, live in the same house, have the same partner, experience the same suffering, etc.), the differences in their levels of happiness would be reduced by only 10%. The remaining 40 per cent is related to people’s behaviour. The key to increasing happiness, Lyubomirsky concludes, lies not in changing genetic factors (which is impossible) or circumstances, but in the actions we take on a daily basis, intentionally.

Happiness that leaves us out of breath

Physical activity goes hand in hand with happiness, researchers at the University of Cambridge found in a 17-month study. Participants downloaded an app that asked them to rate their mood at different times of the day and then answer questions about how active they had been in the previous 15 minutes.

The volunteers reported feeling happier after moving around in the previous 15 minutes compared to sitting or lying down, even though their physical activity was generally light. The study also found that people who moved more were more likely to consider themselves happier than those who spent most of their time in a chair. Although researchers have not established whether physical activity makes us happier or whether happiness makes us more physically active, it is clear that there is a positive association, direct or indirect, between happiness and physical activity, which has been found in several observational studies.

Researchers from the University of Michigan analysed 23 of the most relevant studies on the link between physical activity and happiness. Most of the studies analysed were observational, and a few were experimental—people started exercising and the researchers measured the intensity of their happiness before and after they became more physically active. In total, these studies involved more than 500,000 people of different ages (from teenagers to the elderly), from many ethnic groups and with different socioeconomic statuses. Each study found a link between physical activity and increased happiness, regardless of the type of exercise or even the amount of time spent exercising—even 10 minutes a day was associated with better mood.

Exercise is like an intravenous dose of hope. And it’s any form of movement that you’re willing to do with any part of your body that you can still move,” says Kelly McGonigal, a lecturer at Stanford University. For those struggling with depression or anxiety, McGonigal says clinical studies show that 20 to 40 minutes of physical activity, including gardening or walking, done daily or at least a few times a week, can have significant benefits. There are also studies showing that just 2-3 minutes of exercise can boost a person’s energy and mood for several hours.

When our muscles contract, they release specific substances called myokines that make us more resilient to stress and help us recover from trauma. This, says McGonigal, proves that exercise does a truly incredible job of allowing us to see our body as a trusted ally. The myokines released by regular exercise could even suppress tumour growth, helping to actively fight cancer cells, according to a 2022 study by researchers at Edith Cowan University.

Gratitude, the soil in which happiness can grow

After analysing several dozen experimental studies, researchers Dunigan Folk and Elizabeth Dunn concluded that there is strong evidence for the benefits of expressing gratitude. Gratitude makes us feel better, the studies show, but the effects don’t seem to last more than a day—all the more reason not to deny ourselves the experience of gratitude too often.

Psychologists Robert Emmons and Michael McCullough asked participants in a study on gratitude to write a few sentences each week. Those in the first group were asked to write about the things they were grateful for that week, while those in the second group were asked to write about all the irritating or unpleasant things that happened each day. Those in the third group were asked to write about events that had affected them, without emphasising whether they were positive or negative. After 10 weeks, the volunteers who expressed gratitude for what they had experienced were more optimistic and satisfied with their lives, were more physically active and visited the doctor less than those who focused on unpleasant events.

Psychologist Martin Seligman tested the effects of various positive psychology interventions on 411 people who were asked to write about their early memories. The biggest impact—a huge increase in happiness scores that lasted for a month—came from the task of writing and personally delivering a letter of gratitude to someone who had never been properly thanked for their kindness.

Happiness in the time spent with friends and family

The mere presence of other people in our lives is a happiness-enhancing factor, according to a study by US researchers on a sample of 222 college students. Comparing the happiest with the unhappiest participants, the authors of the study found that there was one major difference between the two groups—the happiest students spent less time alone than the least happy. However, it’s not so much the number of people you have close to you, but the quality of your relationships with them, according to a study which found that a significant predictor of happiness is the quality of your friendships.

The happiness of our friends contributes to our happiness, according to researchers Nicholas Christakis and James Fowler. The pair found that in social networks, happiness can be contagious up to three degrees of separation from its original source (within a network, we can talk about the “distance” between two people, or “degree of separation”). So a person is one degree away from their friend, two degrees away from their friend’s friend, three degrees away from their friend’s friend’s friend, and so on. Researchers have found that happiness spreads up to three degrees of separation from someone who is happy—if a person is one degree away from someone who is happy, they are 15% more likely to be happy themselves. At two and three degrees of separation, the chances of happiness contagion are nearly 10% and 5.6%, respectively.

As happiness expert Daniel Gilbert points out, “We are happy when we have family, we are happy when we have friends and almost all the other things we think make us happy are actually just ways of getting more family and friends.”

Doing good for others makes us feel good

Surveys of adults around the world have found that nearly a third of the world’s population has donated money to charity at least once in the past month. Researcher Elizabeth Dunn points out that studies have shown that people who donate are happier than those who don’t, regardless of their financial situation. In fact, the act of giving has the same effect on happiness as doubling your salary.

While depression, anxiety or stress are associated with a degree of self-centredness, focusing on the needs of others removes negative emotions, explains bioethics professor Stephen Post. When we help another person, we enter a loop of goodness, says Post: doing good makes us feel good, and that good feeling makes us more likely to do good.

Professor Martin Seligman points out that of all the activities that scientists have tested so far, altruistic acts have produced the most significant increase in wellbeing.

This is good news for happiness seekers, who are both fascinated and confused by the contemporary model of happiness, which involves the assiduous pursuit and display of that prized feeling. If happiness has only 10% to do with our circumstances and four times as much to do with our behaviour, then at its core it remains a verb. It’s just that we have to choose our verb wisely, as Sonja Lyubomirsky observes: we can’t wait for it to appear out of nowhere, we can’t hunt it down in all the places we imagine it might wander, but we build it. Day by day, we allow those around us to bask in its light, while we drip kindness and care over the troubled moments of someone less fortunate than ourselves.

Carmen Lăiu is an editor at Signs of the Times Romania and ST Network.