Start using a Heart Rate Monitor

What’s the use of a heart rate monitor?
1) You don’t have to stop occasionally to measure your pulse.
2) You can set the alarm so whenever you are too low or too high (if you prefer: when you are out of your training zone), the alarm will remind you to accelerate or to slow down a bit.
3) You can set the timer to remind you when to stop the workout.
4) At the end, you’ll see the statistics (average heart rate, maximum and minimum HR), sometimes even the total time you exercised in your target zone.
You can put all of this to a chart and this will motivate you more than you imagine. I was so amazed with these numbers that I entered them after every workout and was impatient to do. You can even add your morning weight and calculate the daily or weekly progress. Amazing! I did it after two months since the beginning f my program and it was one of the most motivating things I used.

As it was written on About.com - Sports Medicine, Heart Monitor is a gadget you can live without, but once you try it, you’ll be hardly able to continue without it.
Right, you become addicted! You find it so easy to use and so useful, that you want one during each of your workouts. HRM is not a tool for advanced athletes (although they use them, too). You can find them in various shapes, with so different characteristics – from base models, to fitness and running or cycling computers. Every one will monitor your heart rate in real time, most of them have the chronometer, most will be able to set your five heart zones (but you’ll have to enter your maximum HR yourself), some can even calculate your calories consumption during the workout. Mostly, they have a timer, so you can set the time you want doing your workout (ex: 24 minutes) and will remind you that your exercise is over.
The advanced ones will show you the distance you walked (or ran) – based either on GPS signal or by using a foot pod. Some will even allow you to set your workouts on a computer and to transfer them to your watch and exercise according to the programmed session. Some of the famous brands are Polar, Timex and, recently, Garmin. Polar and Timex have basic to advanced models, Garmin only the advanced ones. I would not recommend the Heart Rate Monitors without a chest strap because they are not accurate.
Basically, you moisten your chest strap and put it on your chest, start your watch in chronometer mode and GO! Don’t forget to warm-up and cool down!

Timex Bodylink	Polar F4M	Garmin 305