In our last two articles we discussed the different stages of fatigue and the importance of implementing a fatigue management plan. In this article we will now look at some simple field based assessments that functional training instructors can use to determine if their clients are currently experiencing excessive fatigue, or even overtraining. This test can be easily conducted by taking a manual pulse measurement in both lying and standing positions or, if you possess a heart rate monitor, you can easily follow the procedures outlined by Polar as follows.
The test result, i.e. the orthostatic heart rate, is the difference between the heart rates at supine rest and at standing position. For example, if the average heart rate in a lying position is 56 and at standing 80, the orthostatic heart rate is 24 bpm.
Performing the Orthostatic test
- Wear the transmitter and the wrist unit. Turn the wrist unit to a mode where you can see your heart rate.
- Lie down and relax. It is recommended to relax at least 3 minutes.
- Check your heart rate, and write it down.
- Stand up and stay standing.
- Check your heart rate, and write it down. You can use the peak heart rate i.e. the highest heart rate or the average heart rate after the peak. If you use the heart rate after the peak, stay standing at least 3 minutes. Note, that you should always use the same value, either the peak or the average.
- Subtract the lying position heart rate from the standing position heart rate. The result is called the Orthostatic Heart Rate:
Orthostatic HR = ( HR at standing ) – ( HR at supine position )
The aim of this test is to determine if there is overactivity in the sympathetic nervous system, which is believed to be correlated with an increased orthostatic heart rate. Upon standing, the body must accommodate the large redistribution of blood volume by decreasing blood pressure and increasing heart rate. The exact difference between what the lying and standing heart rate is hotly debated among researchers and coaches alike, however most seem to agree that an increase in peak heart rate 15 seconds after standing up should not be more than 15 – 30 beats. However, I have had heard other experts suggest, even a difference of 6 beats, could indicate excessive fatigue! In final analysis, it may be even more reliable to conduct your own data analysis, by taking regular measures of your clients orthostatic heart rate (ideally when they are not training to hard) and use the average of a weeks measurements as their baseline. To conclude, using a simple test such as the orthostatic heart rate assessment can easily help you identify if your client is accumulating more stress than they can recover from, and ultimately be at risk of injury. In our next article we will look at some subjective measures of fatigue and how you can combine both objective and subjective measurements to comprehensively monitor your clients fatigue levels and wellness.
- Uusitalo, A. L. (2001). Overtraining: making a difficult diagnosis and implementing targeted treatment. The Physician and Sportsmedicine, 29(5), 35-50.