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Perceived Exertion - A natural way to measure Bio Feedback

An article by Mike Schultz CSCS of Highland Training

Perception is the process of attaining awareness or understanding of sensory information. Muscle soreness, increased breath, and lethargic feelings are some of the sensory information related to exercise. Exertion is defined as the expenditure of energy from skeletal muscle and can be measured by the rate of oxygen use, body heat and heart rate. The way you perceive each exertion during or after exercise is a form of bio feedback that can help you understand your limits to intensity and level of fatigue during training.

The ways you interpret exercise induced fatigue and perceived exertion (PE) are very similar. Both perceived exertion and fatigue share the same physiological feelings of muscle soreness and increased breathing rates but differences between the two concepts exist. Fatigue is closely related to a decline in performance, lack of focus, and lethargic feelings while perceived exertion is more closely related to an individualized measure of exercise intensity.

Certain questions should be answered, while exercising, in order to use PE as a guide to your exercise intensity. You need to ask yourself – Does the hill look hard? Does this hill feel hard? Do my legs feel sore while running or cycling? You are most likely experiencing a high PE if the hill looked hard, felt hard, and legs felt sore. Other forms of bio feedback can be looked at such as your breath and heart rate. Was your breath easy or labored while climbing the hill? Did it feel easy to raise your heart rate or was it work to keep your heart rate elevated at a certain sub-threshold/race pace zone? Learning how to read the feedback your body gives along with your perceived exertion will help you determine your limits for your daily training intensity and durations.

PE is best used when comparing it to other forms of bio feedback such as your heart rate, your breath, or your pace. There are going to be days where you are rested and your PE feels low working at your race pace or threshold heart rate. There are also going to be days where your PE feels high when working at your race pace or threshold heart rates. The days of low PE feelings usually come within the beginning of a training period and after a week of rest. After a week of rest you may experience a low PE for the entire duration of your first few workouts. This is a really good sign of a well functioning and rested system.

A low perceived exertion is the goal when racing. A good program will help you feel a low PE at the beginning of every race. A low PE at the beginning of a race will allow you to focus on other things such as technique and strategy. It is understandable to experience a high PE towards the end of any race, especially the ultra distance events. The increase in PE towards the end of high intensity exercise sessions, such as a race, has a close relationship to the loss of glycogen within the muscle. It is well believed that the rate of carbohydrate absorption is going to be less than what you will need to expend during a race. So the negative balance in energy supply and demand will eventually lead to an increase in PE.

Pushing past your feelings of PE and ignoring the signs of fatigue is a very common mistake made by many. Feeling a higher than normal PE while training is somewhat the goal but it is also the goal to recognize it and reduce your training intensity and volume. The combination of high intensity days, long duration workouts and races will lead to a higher than normal PE over time. A high PE has been closely related to a decrease in power, speed, and overall performance. Learn to listen to your body and work smarter, not harder, towards your goals.

Mike Schultz CSCS