For eight years, I ran through a county park in Southern California where I routinely passed three women leisurely walking and chatting.
All three, by my estimation, were clinically obese and in dire need of losing weight. I took that run one last time prior to moving to Colorado and I'm sorry to say those same three women looked no different than the first day I saw them.
After eight years of walking, I doubt if they had lost a pound between them. How could that be? Quite simply, they did not understand the principles that govern aerobic conditioning.
There are four variables to manipulate in any aerobic exercise routine.
Mode is a fancy word for the exercise you are doing. Are you walking, running, cycling, snow shoeing, swimming, stair stepping or attending an aerobic class? Cross-training, using a variety of aerobic activities, is the safest and most effective way to train.
Frequency speaks to how often one exercises. A balanced exercise routine calls for two to three days of strength training alternating with three to four days of cardio-respiratory (aerobic) conditioning equaling six days a week with a day off for rest and recovery.
How long your exercise session lasts is known as duration. The American College of Sports Medicine calls for aerobic exercise sessions between 30 to 60 minutes. The benefits realized above 60 minutes are minimal and the injury rate significant. Aerobic exercise can be done in two or even three short sessions per day and still yield results.
The final variable of an aerobic exercise program is intensity. If overdone, intensity is a fast track to injury. However, if you do not work intensely enough you will not attain the desired results.
There are two methods of gauging the intensity of an aerobic workout:
The first is age-predicted target heart rate (THR). The formula for calculating your training heart rate for a minute is: THR = 220 minus your age times 60 percent for the lower intensity range and times 85 percent for your upper range. For example I'm 55, my lower range is: THR = 220 minus 55 times 60 percent, which equals 99 beats per minute. My upper intensity range is found using the same formula substituting 85 percent, which yields 140 beats per minute.
It's unlikely I would gain any significant cardio-respiratory benefits training below 60 percent of my THR and statistically, the injury curve spikes dramatically above 85 percent.
One method of tracking your heart rate during exercise is by taking your pulse with your index and middle finger at your carotid artery for ten seconds and multiplying that number by six. Another means of measuring THR is to use a heart rate monitor, which is comprised of a strap that goes around your chest that relays your heart rate to a watch worn on your wrist.
A third method of gauging aerobic intensity is called the Borg Perceived Exertion Scale. This method uses an individual's perception of the degree of difficulty of the exercise as a guideline.
The Perceived Exertion Scale calls for workouts for people just starting out to be between "light to somewhat hard." Intermediate and advanced exercisers should train between a perception of "somewhat hard to hard."
It's OK to spike at "very hard" during a workout but don't live there. Train smart. Life is a marathon, not a wind sprint.