You need to check on all parts of your physical health before undertaking a new fitness program. Generally, it is recommended that you check with your doctor who knows the state of your physical health.
It also is a good idea to keep a workbook with the following test results:
1) Body Mass Index is an indicator of how your weight and height can determine the body fat you have.
For example, a BMI of 30 or more can directly affect your health by 50-150%. This website also has a calculator that adjusts the BMI for age which will give you the weight percentile which compares you to other Americans.
2) Always check the estimated calorie requirements to see how you are maintaining your present weight. Regardless of what you believe you are eating, the figure of daily calories yu are consuming will help to keep your food intact in the reality of calories consumed.
2) On one page you can (a) calculate the distance, time, pace and speed, (b) calculate the BMI (Body Mass Index), (c) calculate your target heart rate, and (d) calculate you body fat percentage.
3) You may be interested in learning the calories expended for different types of exercise.
4) Understanding your training heart rate by Vicki Pearson includes the talk test which is universally used. It means that if you can easily talk during exercise, the exercise may be too easy, if your talk is gasping and hard to do, the exercise is too hard. Taking the count of your heart is easy also. Be sure to measure your heart rate when resting and check the appropriate training heart rate according to your age. She introduces the Karvonen Formula which is the most affective.
5) Be sure to monitor your heart rate by checking it before, during, and after exercise. Check your pulse at your neck, wrist, or temple with two of your fingers. Don’t use the thumb which has a pulse of its own. Know your target heart rate for your age and don’t go beyond 70% of it. If you ever feel dizzy or lightheaded, stop immediately to give your body time to regroup. Live down on your back. Don’t fall for the “no pain, no gain” mindset. Exercise should be done with exertion that is comfortable and enjoyable.
6) If you are interested in learning how to exercise at your desk, this site gives several suggestions.