How much will running against the wind slow you down?
Running against the wind does slow you down. However, there are a number of factors that will influence how much like your age, speed, and fitness level. Regardless though, everyone uses more energy when running against the wind. For instance, one researcher found that oxygen consumption—and ultimately energy cost—increases with the wind while another researcher found that you only get back about half of what you put into running against the wind when you turn around and run with it at your back.