Why gyms need to not smell like gyms

Scientists have put forward a couple of new reasons why gyms need to smell a bit different. 

The first is a study showing that 30 to 40 minutes of moderate to vigorous physical activity daily substantially lowers the health risks associated with a modern sedentary lifestyle. But to spend that time in the gym, you need to not be put off going to the gym.

The second is a little more left field. US researchers say they have found that that smell may play an important role in motivating mammals to engage in voluntary exercise.

Let’s start with the one we can’t ignore. What the study published in a special issue of the British Journal of Sports Medicine is saying is that we can compensate for sitting around all day by exceeding the weekly recommended physical activity levels. 

It’s the first time a recommendation of this kind has been made and reflects, the authors say, a large and growing body of evidence linking extensive sedentary time to serious ill health.

In the latest study, researchers analysed data that tracked how more than 44,000 people from four countries moved, revealing that a high daily tally of sedentary time (defined as 10 or more hours) is linked to a significantly heightened risk of death.

The study coincides with the release of the World Health Organization’s updated guidelines that recommend adults break a moderate sweat for 150-300 minutes a week or engage in vigorous activity for 75-100 minutes a week. But any level of exercise is better than none.

The guidelines reflect “the best available science”, says Emmanuel Stamatakis from Australia’s University of Sydney, a co-editor of the journal issue, but there are “still some gaps in our knowledge”.   

“We are still not clear, for example, where exactly the bar for ‘too much sitting’ is. But this is a fast paced field of research, and we will hopefully have answers in a few years’ time”. 

By then we might also know whether a team from the University of California Riverside is onto something.

To try to determine genetic contributions to voluntary exercise-related traits, Sachiko Haga-Yamanaka and her team subjected mice to voluntary wheel running (VWR). Some had been selectively bred to show high VWR activity, while others were controls.

To their surprise, they found that high-runner mice developed genetic differences in their olfactory system that made them perceive smells differently from the controls.

Several chemosensory receptors in specific receptor gene clusters were differentially expressed between high runners and controls, Haga-Yamanaka says, suggesting they are “important trait locations for the control of voluntary exercise in mice”.

The possible implications for humans are hard to miss, adds colleague Theodore Garland. “It’s not inconceivable that someday we might be able to isolate the chemicals and use them like air fresheners in gyms to make people even more motivated to exercise”.

The researchers now plan to study particular chemicals produced by mice, perhaps from their urine, to try to determine if and how they increase motivation for exercising.

The findings are published in the journal PLOS ONE.