Between 2001 and 2016, the prevalence of physical inactivity increased by more than five percentage points in high-income western countries, to 36.8 per cent, according to the findings of a recent World Health Organisation (WHO) survey. Women in particular are not obtaining the amount of exercise they need: 150 minutes of moderate or 75 minutes of vigorous exercise per week. As I am training for the Dublin marathon it would seem I am a rare enough commodity: an active middle-aged woman. But my smugness has been short-lived.

Last Monday I was out running with two other women. We were subjected to three instances of harassment. They ranged from catcalling and jeering through to threatening behaviour, including one of us being shadowed by a group of men. They chased her down the street while jeering and heckling at 7pm, in broad day light. It wasn’t pleasant.

We were running as part of a bigger group and on our return we checked with our male counterparts – none of them had experienced the harassment we had on our route.

Debate Available research indicates that the vast majority of women runners report that they have been harassed while running. Large surveys in the UK and the US, featured in Time magazine and Runners World, have highlighted this supposedly surprising finding and have ignited a debate on Twitter under the hashtag #runningwhilefemale. Upwards of 90 per cent of women runners report harassment experiences in the UK, for example.

As I raised my experience with colleagues and students in the University of Limerick, online and offline, a few things have become clear.

Second, such harassment is an issue for, and an important deterrent to, women who want to exercise. Students in their early 20s told me they had given up walking outdoors. Imagine, in Ireland in the 21st century, young women opt into a sedentary lifestyle to avoid harassment.

Third, we are far too accepting of this type of behaviour by young men.

A group of graduate students were very surprised that I had bothered to report the incidents. In one student’s words: “It would never even dawn on me to report it.” For them this type of behaviour was an everyday, unremarkable backdrop to their lives.

In social psychology, we often talk about the most powerful forces being those that are banal or assumed. And here is a very clear example of that: despite the problem being endemic, when I reported the harassment people were surprised, almost incredulous, that three such instances could occur in less than 30 minutes. Of course they were surprised: this is not something that has been drawn to their attention previously.

Social activity The men who heckled us doubtless saw their behaviour as harmless fun. One group responded with jeering and joviality when I reprimanded them. Another looked astonished. And so another unremarkable feature of this practice is that it is men who harass women runners. And it is men plural, for the most part jeering and catcalling women runners, for whom this a social activity.

These groups of men either don’t have or don’t want to have any perspective on how their behaviour might be received by women – the intergroup dynamic, in social psychology parlance. Their concern is how their behaviour is viewed by their male peers – an intragroup concern. And because it is a behaviour that is practised socially, we can say within these male groups this type of sexual harassment is acceptable.

In the wake of the WHO findings on exercise, media reports exhorted us to get out and get active. Our everyday behaviour is shaped and structured by the groups to which we belong, with gender probably being a profoundly important group in terms of guiding and shaping behaviour. It is writ particularly large with reference to sport. A colleague told me that in order to feel safe, she had to work hard to pack in her marathon training during daylight hours.

Encouraging women to engage in exercise such as running and walking requires more than health messaging. More than checklists for women so that they feel safe running. We need well-lit outdoor spaces. We need zero tolerance for men who engage in on-street harassment. Men, onlookers and runners need to report every instance of harassment. Failing that can we at least acknowledge and talk about this problem.