Many people who do cardio exercise think that running outdoors provides the same workout as running on a treadmill, but it does not. Running on a treadmill usually provides a pretty stagnant workout. Yes, incline and speed can be changed at will, but feet on the pavement is better. A runner can set their course on a treadmill and see how many calories they are burning and what their expected incline and speed will be, but running on the road sometimes provides unexpected and new routes that will challenge runners to burn more calories as they go up more hills than expected or venture into new territory that may take them on a more roundabout route.
Outdoor running provides a more challenging course as outdoor terrain provides hills, turns, steps, curbs, grass, sand, and pavement. When running through a city, runners can find turns to navigate around at almost any street or bend providing them with angles that challenge different parts of the legs and even the obliques. Running at those angles is unachievable when running on a treadmill that keeps the runner in one straight up and down motion. Running on sand and grass gives the runner more advantageous impact for muscle development.
Running also challenges the reflexes because there are cars on the road, traffic lights to respond to and other people to navigate around. Starting and stopping is a constant motion when responding to traffic lights, navigating around other people challenges the runner’s angles and speed, and looking out for and being aware of cars keeps the runner in a state of awareness that works their reflexes. Outdoor runners also have the advantage of breathing fresher oxygen which keeps their circulation healthier and more oxygenated, allowing them to work out harder and challenge their bodies more.