I am a personal trainer and have a question regarding a client who can't get her heart rate to go over 150 bpm. She's 40 years old and I have set her cardio program to aim for 20 minutes in her target heart rate of 140-160 bpm. I have watched her take her speed and resistance up on the elliptical, the treadmill and the recumbent bike untill she looks maxed out breathing wise and well beyond the talk test limits in my opinion, but her heart rate never goes higher than 150 bpm. Any ideas?
To address your question I must ask some questions. The first and most significant question is has an MD cleared your client for exercise? And was that MD a cardiologist? And if so, how did the stress test turn out? The stress test might give you a little training data. The data will show any problems occurring with the electrical system of her heart, maybe some type of conduction block. There are many different types of conduction blocks, but they all interfere with heart rate. The MD will be able to explain anything that seems unusual. If everything is fine, then you guys are good to go. Then you can look at the data and find the point where her heart rate took a “jump” in rate and use that “elbow” to determine what her training heart rate should be.
Some other questions that need answers are: what training value have you prescribed? Are you using the Karvonen formula to determine the training value, and where on the Borg scale does she tell you she is during a training session? Is she on any medication that might “blunt” her heart rate or metabolic disorders that preclude her from maximal efforts? How about her blood pressure during rest and work, as well as resting heart rate? I am sure you have covered these things, but they are not included in the question, and you know what can happen when you "assume" something.
It is sometimes difficult to determine what a person’s training heart rate should be versus what it is. The 220-age to determine maximum heart rate is a theoretical rate. Some people fall under it, some go over. The only real max is found by getting hooked up to a 12 lead EKG, jump on the treadmill and go until you blow. After a max is determined, multiply your intensity value and get your training parameter, like you have done. And if I am reading the question correctly, you have prescribed a value between 80 and 90 percent max heart rate when using the “straight” training heart rate formula. The only trouble is that your client does not fit the general formula. Now the question is why?
To answer the “why,” you have to investigate her history for any previous problems, illnesses, heredity and "forgot to tell you" medications. At this time, my suggestion is to keep her training intensities light to moderate and treat the 150 bpm as her maximum. This will give her enough stimuli for change and keep both of you safe until you figure things out.