Men's Health The ’20-5-3′ Rule Prescribes How Much Time to Spend Outside To understand what was happening, I met with Rachel Hopman, Ph.D., a neuroscientist at Northeastern University. She told me about the nature pyramid. Think of it like the food pyramid, except that instead of recommending you eat this many servings of vegetables and this many of meat, it recommends the amount of time you should […]