If you are using walking in conjunction with a weight loss program, burning lots of calories should be the number one priority. Daily walking for 40 to 60 minutes at a moderate intensity can burn a substantial amount of calories and may reduce appetite in some people. Increasing the intensity of exercise while maintaining the same duration will burn more calories. However, risk for injury increases with high intensity exercise, and injuries can limit your ability to continue exercising. In order to minimize injuries, substituting other activities such as cycling, rowing, or stair climbing on several days of the week may be helpful.
Some people use walking as a stepping stone to eventual jogging.
Eventually jogging can be done for the entire exercise session. Although heart rate is a good indicator of your exercise intensity, other physical cues can be useful in determining an appropriate work rate. As a rule of thumb, if you can't carry on a conversation you're walking too fast. It is not necessary that everyone take their heart rate when exercising. However, if you want to monitor your intensity closely, taking a heart rate may be helpful.