Zoning in on Peak Performance

by Ellen E. Sampson 

Although running at less than 80 percent of your maximum heart rate (Max HR) has many benefits, you must also train above that number if you strive for better performance.  Training in the upper two HR zones - Anaerobic threshold and Red Line - will be hard, and even painful, as your body accumulates lactate and lacks enough oxygen.  That’s the major reason performance improves. 

Anaerobic Threshold Zone 

In the Anaerobic Threshold Zone of 80 to 90 percent of true Max HR, most fit people will reach their anaerobic threshold (At) or that point when you become short of breath and go into oxygen debt.  To estimate your At HR, take your average HR during the middle of a 5K race and subtract approximately five beats. 

By training in the Anaerobic Threshold Zone, “at, about or around” your At HR, you are teaching your body to sustain a higher HR before your performance suffers. 

If you incorporate at least two weekly workouts at 80 to 90 percent of Max HR in your training program, you will see significant improvements in speed as well as lower HR at the same speed. 

As your At HR moves up closer to your Max HR, your body is better able to distribute more oxygen and nutrients (i.e., energy) at higher exercise intensities.  Hence, you can perform better with less effort.  In other words, you can run faster at a lower HR. 

Red Line Zone 

Only the extremely fit should even consider training in the Red Line Zone at above 90 percent of Max HR.  In this zone it feels like you can’t get enough oxygen and specific muscles burn.  It is the best zone to reach peak performance, but if you spend too much time “red-lining,” you can suffer performance losses or decreases which will require long-term recovery.  Overuse injuries, staleness, and cumulative fatigue are just a few of the potential negative impacts. 

By limiting your Red Line training to interval workouts which allow you to do short, hard, high HR intervals followed by easier recovery intervals, you can reduce the risk of long-term damage.  As a general rule, no more than 25 percent of your weekly training “time” should be in this zone. 

Having learned how differently the body responds cardiovascularly and metabolically from training in each of the HR zones, you are now ready to prepare your own heart zone training program.