Have you ever been inspired to do your own run by your friend's smug post on social media about the 10k run she just did in the pouring rain? Turns out you're not alone. According to a new study published in the scientific journal Nature Communications, exercise could be a contagious thing – especially among women.
Sinan Aral and Christos Nicolaides, the authors of the study, analysed the data from 1.1 million people's exercise trackers over the space of five years. During that time, these people ran a combined 350 million kilometres. All the runs were shared on a social media platform.
What Sinan and Christos found was that, well, we're not happy with other people gaining on us in terms of exercise. If a person runs one kilometre further than usual, it could inspire their friend who usually runs more, to run 0.3 kilometres further. If a person runs faster than usual, their friend who normally runs faster than them anyway could in turn run 0.3k per minute faster themselves.
The contagion only works in certain ways, though. Less active runners influence more active runners – but not the other way around. And both men and women influence men, but it's only women who influence other women.
The study does note that these estimates are only "suggestive". Nevertheless it makes for some interesting reading.
"Social comparisons may provide an explanation for these results," write Sinan and Christos. "Comparisons to those ahead of us may motivate our own self-improvement, while comparisons to those behind us may create ‘competitive behaviour to protect one’s superiority’."
So that's nice, isn't it? Rather than contagion in exercise being down to shared positivity and spurring each other on, it turns out it could be down to us trying to be as good or better than other people.
Nevertheless, we all know that getting out there can be tough. Sometimes heading out for a run is the last thing you want to do. So hey, if it takes a bit of ego-massaging to give you the kick up the arse that you need, then that's probably OK – maybe just don't mention it to anyone else.