3 ms·

You seperate out the variables and study people who can exercise, but don’t?

• barry-cotter 7y ago
  People who exercise are different from those who can but don’t, just as those who smoke are different from those who could, but don’t. People who exercise almost certainly have higher energy levels to start with and are less likely to have lingering minor injuries, just as you’d expect smokers and former smokers to exhibit higher levels of addictive behaviour like high coffee or cola consumption than never smokers. Epidemiology and nutrition have massive problems teasing out causation because people who X are different from people who don’t X in many more ways than in just that difference. The health benefits of wine over beer probably reflect socioeconomic differences in consumption for just one example.
  • lm28469 7y ago
    If you think like that you quickly stop looking at studies, it's impossible to control for every variables, even for the most simple phenomenons. We do our best and most of the time it's enough.