Understanding Exercise Intensity and Rate Pressure Product (RPP)
“One has to get in shape to get in shape”. This simple tagline sounds like a redundant thought but actually underscores the importance for personal trainers to understand and put into practice appropriate starting points and progressions for their clients. Individuals who hire certified personal trainers are often looking for rapid results. However, human physiology has its own pace regardless of the goal. Certainly, water weight can be reduced quickly by cutting carbohydrates, but for effective long-term weight loss goals to be met and sustained, proper progression is necessary. Starting a new exercise program too aggressively is a pitfall for many personal trainers. Those who have years of experience and the appropriate knowledge and understanding of key fitness concepts such as Rate of Perceived Exertion (RPE) and Rate Pressure Product (RPP) consistently implement appropriate starting points for new clients and effective short-term goals that are achievable and build upon each other, resulting in long-term goal achievement.
Rate Pressure Product (RPP) in particular is a commonly misunderstood component that can present early limitations to success. RPP is defined by resting heart rate (RHR) multiplied by systolic blood pressure (SBP). Any total value greater than 10,000 indicates an increased risk for heart disease. What RPP really illustrates is the oxygen demands of the heart. One must remember that the heart is a muscle, and just like any other muscle in the body it requires a steady supply of oxygen in order to function properly. For a person who is in good physical condition the oxygen demands of the heart place less contributing stress in a workout, whereas a deconditioned individual experiences an elevated stress from cardiac demand and the fatigue of respiratory muscles attempting to satisfy this demand. Hence the reason people get out of breath with slight exertion. To give an example, an individual who is deconditioned (RHR = 85 bpm) and has hypertension (blood pressure of 140/90) would have a RPP of 11,900 (85 x 140 = 11,900). That individual not only has an increased risk of heart disease but also has a very large stress on the heart with regard to oxygen delivery needs. This results in a faster onset of fatigue during moderate exercise and an increased rate of perceived exertion (RPE) during all submaximal activity. Compare the previous example with a cardiovascularly fit individual (RHR = 65 bpm) with a healthy blood pressure (120/80) and the RPP is only 7,800. This indicates that the heart is fairly efficient in its oxygen consumption and therefore results in a lower RPE during submaximal activity. The fittest individuals have resting RPP level around 5,000.
How does this simple calculation help personal trainers? And why is this relevant to the personal training profession? New trainers tend to push too aggressively in attempts to validate themselves and help their clients to see instant results at the start of a program. The result during a prematurely difficult training session is an early onset of fatigue and an uncomfortable experience in attempts to manage the exercise stress. It would be more beneficial to the client to work at a slightly lower intensity allowing them to sustain an elevated HR throughout the entire duration of the training session thereby resulting in progressive cardiovascular improvements over time (e.g. decreased resting HR and lower blood pressure). When RPP is then re-calculated weeks into a training program, these physiological adaptations (lower RHR and SBP) will result in a lower RPP and demonstrate a reduced risk of heart disease as well as an increased capacity for work. As the RPP continues to decrease, life expectancy increases and training intensities can be increased in a positive linear fashion. And what better improvement can a personal trainer show a client than an increase in both life efficiency and expectancy? This is only possible, however, if proper progressions are practiced from Day 1. This starts with personal trainers understanding the oxygen delivery demands of the heart and accommodating for the deconditioned myocardial tissue during the orientation stages of a new exercise program. Proper starting points allow for appropriately applied stress which can be adapted to without risk of overstrain which often leads to not only an increased risk for injury but also increased rate of client attrition. Focusing on decreasing resting heart rate and blood pressure via aerobic exercise is also a valuable component to include in early training sessions. Personal trainers that expect clients to perform aerobic training on their own are making an error which will limit rather than accelerate results. Many people do not realize that a solid cardiovascular foundation is not only important for aerobic exercise but also for anaerobic training as well.