On Your Weigh to Wait Loss Part II: Exercise!

Diet and exercise go hand in hand in order to achieve and maintain a healthy weight, but the question has been asked:

"Is it better to exercise at a lower intensity for a longer time or higher intensity for a shorter period of time"?


Although I hate giving this type of answer - it depends.

As we seek to improve our performance at physical activity, we must devote a certain amount of time (duration) and energy (intensity) to that activity.  Mathematically, that equation might look like this:

Training Stress = Duration + Intensity

We have two ways to control how much stress we put on our bodies.  We can alter the length of the exercise, the intensity, or both.  We will discuss the benefits of varying duration and intensity and how it might help us achieve certain goals.

DURATION - "THE BIGGER THE BASE, THE BETTER THE RACE"

Longer periods of lower-intensity exercise are referred to as "base builders".  It is helpful to view this exercise as the foundation of your physical abilities.  Without a strong foundation, the building will crack (manifested as injury) or never live up to its full potential.  We need to spend a long amount of time (sometimes years) to build a strong aerobic base and to condition the body to accept the demands of higher intensity exercise.

Not only does base building prepare the body to be able to produce higher intensity efforts later in the year, it also forces the body to utilize stored fat as a fuel source.  Additionally, the body will literally increase its ability to transport oxygen to the muscles.  These are only a few reasons why base building is  so important.

Base building exercises are usually done early in the year or in the off-season.  A good way to gauge proper intensity for base building is to ask yourself "could I easily carry on a conversation right now'?  If you are gasping for breath and unable to converse, your intensity is too high and you need to slow down a bit.  If you're using a heart rate monitor, you should exercise at 65-75% of your maximum heart rate while base building.

As with any type of activity, you need to gradually work your way up to a three hour run or bicycle.  A good rule of thumb regarding increasing your duration of exercise is to add no more than 10% time or distance to your long run or ride.  DO NOT risk injury just to get a few extra miles or minutes in.

INTENSITY: THE FINAL FRONTIER

In order to achieve the best performance that you are capable of, you need to include shorter periods of intense exercise.  Most athletes fall into one of two categories when it comes to intensity:

1. Not enough (because it hurts)
2. Too much (because I need to get fast...NOW!)

Exercising at a higher level of intensity increases your heart rate and level of respiration, and produces lactic acid within the muscles which is perceived as a fiery ache.  Since this ache is seen as a source of discomfort, most people avoid it altogether.  However, the body has ways of dealing with this high level of stress.

The body is basically lazy.  It does not like to have its routine changed.  It does not like to produce high levels of muscular force for long periods of time.  However, we can trick the body's laziness into helping us meet our desired goals.

The body releases endorphins to combat the pain of the lactic acid within the muscles.  The more frequently we perform high intensity exercise, the body will release endorphins sooner and at a higher dosage, and lactic acid production is decreased.

The cardiovascular system also becomes more efficient in the way that it transports oxygen.

The muscles become stronger.

In other words, the body (which is lazy, remember?) develops ways to deal with the painful experience of high intensity exercise.  After a period of time, the athlete actually begins to develop a craving for high intensity exercise in much the same way a drug addict craves "the next fix".

During high intensity exercise, for a given exercise duration (let's say 30 minutes), the body burns less fat as a percentage of total calories as compared to lower base building exercise.  However, because of the increased intensity, the number of total calories AND fat calories is higher for the 30 minute exercise period.

"So which is better, duration or intensity"?

Duration and intensity are both very important in becoming a well-rounded athlete, but the periods of the year in which we utilize them might be different.  Here are some helpful hints about when to use a higher duration or higher intensity:

Use longer duration:

• for off-season or early season base building
• for teaching your body how to burn fat stores during extended exercise
• once you have exercised for a month or so to increase your aerobic capacity

Use higher intensity:

• once you've established a good foundation of fitness (or "base")
• to teach your body how to buffer lactic acid
• to burn more calories and fat
• to become a faster athlete
• in moderation.  Remember:  higher intensities make the athlete more susceptible to injury.