PRITIKIN PROGRAM: HOW TO GET F.I.T.
Once you know it's safe to begin an exercise program, how hard should you exercise, and how often? The recommendation is to work out continuously at your training heart rate for at least 20 minutes three times a week, and at least once a week just below your THR. To help you with your program, we've developed a personal workout plan that consists of three main variables: frequency, intensity, and time - easily remembered as "F.I.T."
How often you exercise is one factor in generating the results you're looking for in an exercise program. We recommend four to six aerobic workouts a week. That may be difficult, but try not to skip two days of exercise in a row - it can be hard to get back on track when you do. There's also the possibility that your level of triglycerides (circulating blood fats), which is sharply reduced by aerobic exercise, may promptly increase in its absence.
This measure is determined by your training (or target) heart rate - your THR. It's important that your heart stay within this range for you to get optimal cardiovascular benefit; anything less won't give you full benefit, and going above your range will quickly render your exercise anaerobic (not oxygen-efficient), and could be dangerous as well. A general rule is that if you can speak or hum easily while you exercise, you're not overdoing it. Heavy breathing is okay, but gasping for breath is not, since it might mean you're not getting enough oxygen. So at the first sign of dizziness or shortness of breath, slow down, and then stop - especially if you know you're at risk for heart disease. Although it's bard for most people to keep exercising above their THR, a feeling of light-headedness can be a sign that you are - which could lead to an increased risk of injury, an elevation in your blood pressure, or the precipitation of arrhythmia (an alteration in the rhythm of the heartbeat) or ischemia (obstruction of the inflow of arterial blood).
The most accurate way to determine your training heart rate is to take a treadmill test - and for some people, as we mentioned earlier, it's the only safe way. But if you're ready to begin exercising (according to the ACSM guidelines cited earlier) you can simply calculate your general training heart rate. The following formula is, however, not appropriate (and can even be dangerous) for people with some medical conditions (such as high blood pressure) or for those taking certain medications (such as a beta-blocker). Calculating your own THR is appropriate only for those who are not at risk.
Calculating your THR
First, subtract your age from 220 (everyone's base number). Multiply the result by .7 to find the lower limit of your THR, and then by .85 to determine the upper limit. These numbers are your training heart rate range, per minute. However, if you stop to check your heart rate during a workout, don't take your pulse for a full minute - by the time the 60 seconds are up, your heart rate will have gone way down. Take it for a shorter period of time, then multiply the reading to equal a full minute. Many regular exercisers find it easiest just to multiply a 6-second reading by 10 to find out if they're on target.
To take your pulse, use the index and middle fingers of one hand to find your pulse under your thumb on the wrist of the opposite hand. (Some people find it easier to place the index and middle fingers of one hand on their upper neck, right below their jaw, to find their pulse. Either way is fine - just don't press too hard, and don't press on both sides of the neck at once.)
Practice taking your pulse regularly when you exercise to see if you're on target, and try to be conscious of what your body feels like when you're within range. Most people describe this feeling as exertion just above what's easy - when they're conscious of the exertion but can hum or talk easily to a companion, and feel as though they could keep moving for a fairly long time. (Runners often say they're there when their breathing "kicks in." And for some people, it's their "sweat threshold" - but don't count on that as a perfect indicator, since heat, humidity, and individual metabolism make people sweat at different times.) Do try to sensitize yourself to what your THR feels like inside; after a while, you won't need to keep checking your pulse - you'll just have a gut feeling that you're on track.
Hard and easy days
The "I" of F.I.T. - intensity - also has to do with hard and easy exercising days: Our recommendation is that you alternate between them. On a "hard" day, perform any aerobic workout at your training heart rate for a maximum advantage to your heart and lungs. On "easy" days, do the same activity but at 4 to 12 beats (per 60-second count) below your training heart rate, and for a longer duration than on a "hard" day. Exercising both "hard" and "easy" will not only develop your endurance and help you burn fat, but it will also reduce your chances of being injured by overtraining by allowing your body time to adapt (on easy days) to the stress of exercise.
You'll find that the more fit you become, the more "work" it takes to achieve and maintain your THR: You'll probably have to step up the rate of whatever exercise you're doing. But don't worry - you'll be ready. You'll be more fit, and you'll probably want to move a little more by that time as well, exercising most days at your THR.
On hard days, exercise for 30 to 45 minutes at training heart rate; on easy days, exercise for 45 to 60 minutes below your THR, as described above. This is only a general rule, however; if you're just starting an exercise program, simply do the best you can and aim for 20 minutes at first on both hard and easy days. Extend your exercise sessions gradually as your fitness improves, until you reach the recommended lengths of time. Some people may be able to do this quite easily - but be careful not to overdo it! It just isn't necessary (and may be unwise) to log in excessive amounts of time.
If you choose to walk or jog, you might want to wear a pedometer to gauge your distance. Or drive your car along your course to check the mileage. (You can even figure out your walking or running rate if you divide your distance by your time. If, for example, it takes you 24 minutes to run a 2-mile course - including a 3-minute walking break between the first and second miles - divide the 21 minutes you run by the 2 miles you cover. You're running a l0 1/2-minute mile.)