There’s (sedentary) rejoicing in my community, the pathologically lazy, at the news that only 11 minutes of brisk walking a day may save us from early death. Of course, multiple caveats must accompany this statement, distilled from a Cambridge University-led meta-analysis of data on physical activity and heart disease. We would have to be in the lucky 10%: only one in 10 early deaths could be avoided with a brief constitutional. Exercise levels were also self-reported, meaning researchers had to make some assumptions about duration and intensity. And 11 minutes is a neatly digestible take-home from analysing 196 studies with more than 30 million participants, not a magic bullet.
We like a magic-bullet figure though, don’t we? Real-world public health messages ought to be distilled from hard science, but sometimes emerge in the absence of it; as with the persistent “10,000 steps” myth. The World Health Organization’s recommendation of 400g minimum of fruit and veg daily became our five-a-day article of faith, even though 2017 research found upping it to 10 a day could prevent 7.8m premature deaths. Brushing your teeth for the recommended two minutes may only reduce plaque by less than half; four minutes is better. But we’re human: most of us manage 45 seconds brushing and only 28% of adults reported reaching our five a day in 2018 (it’s probably even less now, during the Great Salad Penury).
