The brilliance of the Weight Watchers system lies in its flexibility. Take swimming for example. Lane-swimming can be used to earn the average person two activity points. However, whether you perform at a lower intensity with 45 minutes of water running, or vigorously with 15 minutes of laps, you can earn the same two points.
Activity Points and Exercise Intensity
In its PointsPlus system, Weight Watchers uses your current body weight to determine your daily allotted food points. Activity points are calculated by using your maximum heart rate, or MHR, with percentage of MHR used to determine the intensity of different activities. Weight Watchers uses three levels of exercise intensity to determine the points earned by performing different activities, with low intensity exercise defined as 40 percent to 54 percent of your MHR, medium intensity being 55 percent to 69 percent of your MHR and high-intensity exercise resulting in a heart rate at 70 percent or above your MHR.
Maximum Heart Rate and Rating of Perceived Exertion
To estimate exercise intensity, calculate your MHR by subtracting your current age in years from 220, then measure the heart rate that you achieve while performing a certain activity. Divide your achieved heart rate by your MHR and multiply by 100 to determine the percent of your MHR that you attain while performing a certain activity. If you do not have a heart rate monitor or wish to avoid these calculations, Weight Watchers suggests the use of the subjective Rating of Perceived Exertion. Similarly divided into three levels of intensity, an easy RPE activity does not make you sweat, has little effect on your breathing and has no effect on your ability to carry on a conversation. A moderate or somewhat hard RPE activity makes you sweat after about 10 minutes, causes your breathing to become deeper and more frequent and will affect your ability to sing, though not to carry on a conversation. A hard RPE activity will make you sweat after three to five minutes, breathe deeply and rapidly and limit your conversation ability to short phrases.
If you are just starting your exercise routine, Weight Watchers recommends that you attempt to earn three activity points per week. After you can comfortably do so for a few weeks, Weight Watchers recommends that you move to the second activity stage at which you should attempt to earn seven activity points per week. Weight Watchers recommends that you move on by increasing your weekly activity points by two points per week until you reach 28 points per week. After that, maintain this activity level until you reach your weight-loss goals. At this point, the company recommends that you should move onto the fourth stage, attempting to maintain this activity level while trying new activities and increasing the intensity level of those that you are already performing.
Activity and Food Points
Weekly activity points can be collected and "spent" in the form of increased food points. While Weight Watchers provides this option for those who wish to periodically indulge in comfort foods, activity points do not have to be converted into food points. By increasing your activity level and maintaining a high level of activity points, Weight Watchers suggests that you should be able to reach your weight-loss goals faster. Though you might wish to spend these points on food, alternating spending and saving may help you to quickly lose weight without having to completely abstain from your favorite foods.