Aerobic training is all about the heart rate. You have to get it up to around 120 or higher (and keep it there for a while) to have a training effect. Unless you are REALLY unfit, walking is probably not enough.
You can also run/walk in intervals as long as you keep the heart rate up. If you want to get fit, a heart rate monitor is a great investment (something like a polar h10 can pair with your smartphone).
You can also run/walk in intervals as long as you keep the heart rate up. If you want to get fit, a heart rate monitor is a great investment (something like a polar h10 can pair with your smartphone).