Oprah Best Life recap: Dr Oz discusses resting heart rate for athletes

Dr. Mehmet Oz co-hosted Oprah's second show in her Best LIfe series which premiered Monday and will run for a week. Dr. Oz spent the hour walking viewers through a Ten Step Ultimate Health Checklist which included 'knowing your numbers' as step number five. There are nine numbers to know, according to Oz: blood pressure, cholesterol, omega fatty acid intake, inflammation (as measured by CRP), vitamin D levels, waist size (less than half your height), blood sugar, bone density and resting heart rate. Oz recommends taking the resting heart rate first thing in the morning, noting that a number over 83 is dangerous, but that healthy athletes can have resting heart rates below 50.

With monitors on almost every cardio machine at the gym and portable heart rate monitors commonly available, heart rate is used by many exercisers as an indicator of exertion and fitness level. But understanding heart rate and how to use it is more complicated than Dr. Oz was able to communicate in his hour on the Oprah show.

There are many factors which affect resting heart rate including medications, age, gender, genetics, anxiety, hydration level, and level of fitness. Dr. Oz warned that a resting heart rate exceeding 83 beats per minute warrants concern and this is an important precaution to note. But, a one time resting heart that is moderately high doesn't necessarily indicate lack of fitness or well being. Similarly, a one time low heart rate doesn't necessarily mean that you're ready to take on Lance Armstrong at the Tour de France. In fact, excessive training can cause an elevated resting heart rate. The most effective method of evaluating resting heart rate is to take it over a period of time and to examine the pattern.

As exercisers become more fit and develop a regular fitness habit, they should see a decline in their resting heart rate. It is this decline, rather than the actual number that is a better indicator of fitness and exercise program success. For very active athletes, watching resting heart rate over a period of time is helpful in order to watch for unusual peaks which may indicate overtraining or overstress.

An average resting heart rate is also helpful to know for establishing an appropriate training heart rate. Many posted health club charts or stickers on cardio machines use target heart rate numbers calculated using only age and gender. The Karvonen formula for calculating target heart rate also uses resting heart rate. Since average resting heart rate is an indicator of fitness level, the Karvonen formula tends to be a more effective method for determining appropriate intensity, especially in older fit adults.

For more information about heart rate and the Karvonen formula, read Your weekend workout: Walk this way or visit the American Council on Exercise website