If you have never used one before it is a tool that practically guides you through your workout. Once set, it will let you know when you need to pick up the pace and when its cool to take a break. With the ultimate goal being to burn as many calories as possible during your workout (and to have some fun) a HRM will come in very handy.
Most basic models will do the job. My favorite brand is a Polar HRM. The FT4 version is great for keeping track of your heart-rate and the number of calories burned, and it comes in cute colors. There is no need to research the science behind it, just enter your information and the watch will do the rest. Try your best to keep your heart rate in the zone and you will ensure that you are getting the most out of each and every workout.
Yesterday my Dad invited me to go out to a portion of the Ocala National Forrest to walk a good chunk of the Alexander Springs Trail, which I am pretty sure is no longer a spring because we saw no water anywhere. I was also a little surprised to not have seen any animals, not even a squirrel or a snake but it was still very pretty and peaceful.