Run at least three times a week. A single run should last from 20 to 90 minutes. Begin with a 20-minute exercise session and increase as fitness progresses. For this type of exercise, aim for a heart rate of between 65 percent and 80 percent of your maximum heart rate. Find the maximum heart rate by subtracting your age from 220. This calculation equals the number of heart beats per minute when at maximum heart rate for the relevant age. Multiply this number by 0.66 to calculate 65 percent, and multiply by 0.80 to calculate 80 percent of your target rate. Measure the number of heartbeats per minute by checking the pulse at the neck with the first two fingers.
Incorporate Fartlek training, or interval training, into a weekly schedule by again going for a run. Throughout the run work harder for short periods, while aiming for a heart rate of 90 percent. After a period of 2 to 3 minutes, slow down and aim to drop the heart rate to 65 percent.
Add other cardiovascular exercises that will aid in aerobic fitness. Sports such as cycling and swimming both fall into this category. Aim for an average heart rate of 70 percent throughout these activities. Exercise sessions should last from 10 minutes to an hour or longer to be effective.