This is an excerpt from Heart Rate Training by Roy T. Benson & Declan Connolly.
Overtraining and staleness can be avoided by monitoring heart rate. Bear in mind that overtraining is a complex area. However, you can use heart rate data to indicate too much training in the early stages, what we refer to as acute overtraining, or overreaching.
Overreaching applies to short-term overtraining, as might happen after a particularly hard training session. This usually occurs in the few days following a longer, more strenuous workout. Overtraining applies to longer, more chronic overtraining conditions that result after weeks or months of training without adequate rest and nutrition. This is a more serious condition requiring lengthy periods of rest, nutrition, and perhaps medical intervention. In contrast, overreaching can normally be addressed with a few days of rest and a few hearty meals.
Using your heart rate monitor can keep you from developing either overtraining condition. To use it effectively, you need to do two things:
1. Record and monitor your resting heart rate and exercise heart rate response to a given workload as often as possible. These should be documented over days, weeks, and months.
2. Understand how your heart rate should respond both at rest and during exercise as you train. Make sure it is increasing and decreasing as you would expect.
Addressing the first issue is fairly straightforward. Under normal conditions, resting heart rate should be back to normal within 24 hours of a workout. You should make sure this is the case before proceeding with a higher-intensity workload the following day. Over time, however, your heart rate should decrease both at rest and in response to a fixed workload. The decreased heart rate response under both situations is a result of improved cardiac muscle function—the heart is stronger and can move more blood with each beat. We call this increased stroke volume. If you are not fully recovered, then your heart rate at rest will be elevated because it is still working at repairing tissues and replenishing fuels. What's more, if you are not recovered, your heart rate during exercise will not increase to where it needs to be to supply the needed blood flow. This results in the sluggishness or staleness athletes often experience during early overreaching. It feels as though someone has put the lid on the heart rate. As a result, you try to work harder but cannot because the heart rate cannot elevate to give you the blood supply you need. The result is a frustrating and psychologically damaging workout. Your legs and arms are heavy, and the best thing you can do is go home, eat, and sleep.
It is nice to have your 12-week program carved in stone. However, you need to be open-minded enough to change your daily plan if your body needs it. The question is, What should you do if your heart rate indicates overtraining? The obvious answer to is simply to cut back on the volume of exercise you are doing, especially for the next few days. For some athletes this is not always possible, but there are a few other precautions you can take.
The first step is to determine whether you are in an acute stage of overtraining or overreaching, or whether these are early symptoms of a more long-term, chronic problem. To determine this, we ask athletes three questions. (1) Are you finding your exercise sessions getting more difficult or easier? If they are getting more difficult and they are the same workouts (i.e., same speed), you're overtraining. (2) Are you very tired but having trouble getting good-quality sleep? If so, you are overtraining. (3) Do you find it difficult to exert maximum effort during a routine training session? If so, you're overtraining. These three simple questions will help you determine whether you are starting to overtrain.
Early stages of overtraining are really overreaching. Overreaching generally occurs when there is a marked increase in intensity or volume, which quite often happens to athletes attending training camp where there is a significant increase in workload within a short period of time. The good news about overreaching is that it can be addressed relatively quickly and easily, with three or four days of planned rest and appropriate nutritional intervention.
Ignoring the symptoms and continuing to train with the mentality that you just need to grind through the sessions will inevitably lead to classic overtraining. Classic overtraining is a more long-term problem with more serious consequences. It usually has all the signs and symptoms of overreaching plus a couple more: resting heart rate continues to be elevated at rest, and exercise heart rates continue to be depressed despite efforts to work harder. What follows tends to be a period of illness or sickness as a result of a compromised immune system. At this point you are clearly overtraining and facing several weeks or possibly several months of layoff from exercise.
Fortunately, by monitoring your heart rate regularly both at rest and during exercise, you can detect these early symptoms. Then, you can take appropriate action to vary the intensity and duration of workouts to ensure that you do not move from the overreaching condition into the overtraining condition.
Read more about Heart Rate Training.