Ideas in this flowchart

• Exercise intensity can be measured using heart rate or perceived exertion.
• The two main approaches are heart-rate measurement and the RPE method.
• Heart-rate measurement includes two methods.
• The rating of perceived exertion (RPE) method measures how hard the exercise feels.
• The percentage of maximal heart rate method prescribes exercise at a certain percentage of maximum heart rate.
• The heart rate reserve method is also called the Karvonen method.
• A person's true maximum heart rate must be measured in a laboratory.
• Laboratory measurement is impractical for most people.
• Maximum heart rate can therefore be estimated using the formula 220 − age.
• Example 1 applies the percentage heart rate method to the case of Mariella.
• Mariella is 30 years old.
• Step 1 calculates maximum heart rate: estimated HRmax = 220 − age = 220 − 30 =