Ed McNeely – Peak Centre for Human Performance
Heart rate is an easily measurable physiological variable that is often used to gauge the intensity of a training session. Under the right conditions heart rates can be a useful tool but there are too many athletes that have developed a dependence on their heart rate monitor with little understanding of how to use it effectively.
The ability to use heart rate to monitor the intensity of a training session developed from the fact that there is a linear relationship between oxygen consumption and heart rate. While this is valuable information, it has also lead to two problem areas. First, the relationship starts to break down at around 85% of VO2 max. Since many types of intervals and most speed work are done at or above this intensity heart rate alone cannot be used to monitor this type of work. Second, even though there is a relationship between exercise intensity and heart rate this relationship is different for different exercises i.e. heart rates for running will not be the same as heart rates for rowing for any given intensity. In fact, in cycling heart rates change with different body position on the bike. Some research indicates that heart rates on the road can be as much as 10 beats higher than riding indoors on a trainer for the same oxygen consumption. This brings us to our first rule of heart rate monitoring. Heart rates are specific to the activity you are doing .
Heart rate is influenced by many variables. Duration of training, emotional stress, clothing, heat, dehydration, overtraining, loss of sleep, decreased blood volume, altitude, and detraining. During long duration steady state training sessions the heat produced by the body can increase heart rate by as much as 20 beats/ minute. If you were to slow down to try to keep your heart rate the same, you would change the training effect for the muscles. This leads us to heart rate rule number two: During steady state training the speed or power output should remain relatively constant throughout the session regardless of increases in heart rate.
Training in a hot environment can increase heart rate by up to 13 beats/min. Emotional stress at work or the stress of exams at schools tends to increase heart rate during training. In addition, these types of stress decrease quality of sleep which further increases heart rate. Rule number three: When training in hot weather or during periods of high stress use feelings of fatigue and comfort as a training guide rather than heart rate.
Heart rate is an individual response as is maximum heart rate, varying as much as 20-30 bpm between people of the same fitness level. Comparing heart rates to other people is unnecessary and often unwise. Training programs should not be based on general heart rate guidelines rather they should be based on individual responses. A training heart rate of 150 bpm may elicit very different adaptations for different people. Rule 4: Don’t compare heart rates to others.
Because heart rate is an individual response, heart rate values need to be determined in relation to other physiological variables. There are three common physiological markers for aerobic training: Aerobic threshold, anaerobic threshold and VO2 max. Training programs are normally designed to change these physiological points. To prescribe meaningful heart rate ranges these points have to be identified. This can be done through lactate testing or through an oxygen consumption test. If these points are not determined the heart rate prescriptions are purely guess work. Rule 5: Heart rate ranges should be determined from other physiological data.
Heart rate is a tool for training. Like all tools it has limitation and should be used for a specific job at a specific time. Speed, pace or power output are influenced by fewer factors than heart rate and may prove to be better indicators of training intensity. If you are going to use heart rate to monitor your intensity follow the guidelines outlined here and remember that heart rate is just a response to internal and external stimuli it should not be the main controlling factor for your training.
PEAK Centre staff have the highest certifications available in Canada for Sport Science. With their combined experience and education, PEAK Centre is at the forefront of practical Sport Science application.