B According to new health guidelines, even a minute or two of physical exercise is better than nothing: just walking upstairs and down again, before continuing your otherwise entirely sofa-based afternoon of crisps and television, makes for a healthier life than if you hadn' t bothered. The previous recommendation was for a 10-minute minimum, but for years’ the general direction of research has been toward the conclusion that there is no minimum at all. This doesn 5 1 just go for exercise^ either. Five minutes in nature can boost your mental health; and while one daily serving of vegetables may be too few, it's definitely preferable to zero. If you are wondering whether or not some tiny but healthful activity is worth it, the answer^ almost always, is yes. It' s a little strange^ actually, that this is even a topic of debate. Of course anything is better than nothing. For one thing, it's a good start for building habits. For another, tiny actions are valuable in themselves. Human bodies aren't digital devices, and health generally isn't a matter of reaching fixed thresholds (「[ 槛); what is good for the organism in large quantities is usually good in smaller ones, too. The real reason for the debate is not that the facts are in dispute (争 议) . It's that information is erous. When public bodies recommend^ say, a 10-minute minimum, it's because they worry that if they don't, people who might otherwise have exercised for 10 minutes will stop after two. Even this column risks things worse. If you had truly been planning to spend all day on the sofa, perhaps I have inspired you to take a five-minute walk; but if there is a chance that you would have gone to the gym for an hour, reading these words might persuade you to settle for the stroll (散步) instead. Ideally, we would stop thinking about healthy behaviours in terms of minimums: within reason, you should be doing as much exercise as you can, not as little as you can get away with — while remembering that nothing is too minor to be not worth the bother. This is a sensible approach to much of life, I would say, from being a good friend or paying attention to your kids, to saving money or reducing your environmental impact. However much you do 9 it will never be enough. But that is not a reason to do nothing — on the contrary^ it' s a reason to do something.