Andrew Hamilton explains the phenomenon of ‘cardiovascular drift’ during steady-state workouts. What is it, why is it undesirable and how can athletes overcome it to get a greater training response from their training sessions? MORE
When athletes train too much, problems start to crop up in their nervous, endocrine, and immune systems – problems which can leave the athletes anxious, depressed, low on energy, and vulnerable to infections. Can ‘Rusko’s rules’ help.
Although the chaos in the nervous, endocrine, and immune systems is obviously a bad thing, the fact that overtraining seems to produce its first problems in these three systems has led some scientists to conclude that careful physiological surveillance might help to PREVENT overtraining.
Alternatively, an athlete’s blood could be checked regularly for T lymphocytes, key white blood cells which fight infections and assault tumours. A lack of T-lymphocyte activity, or a decrease in the concentration of T Iymphocytes, would be a sign of immune-system failure and might suggest that an athlete had been training too hard.
The problem, of course, is that monitoring the immune and endocrine systems in this way is expensive and requires medical supervision, making the procedures impractical for most athletes. Another cheaper and simpler strategy, in which athletes simply monitor their feelings of fatigue and reduce their training whenever lethargy persists for more than a day or two, has been shown to be ineffective. The problem is that athletes often report that they are feeling great on the day immediately before they slip into the overtrained state.
Fortunately, famed Finnish researcher Heikki Rusko has developed another way to check for overtraining, and the new technique is very easy to carry out. After working closely with elite Finnish cross country skiers, some of whom became over-trained during 13 weeks of intensified training, Rusko developed a simple ‘orthostatic test’ which can often foretell the troubling condition. To perform Rusko’s test, you simply lie quietly for 10 minutes at the same time every day while monitoring your heart rate, which should stay constant during the 10-minute period. You then stand up and check your heart rate exactly 15 seconds after standing, and then again during the period 90-120 seconds after standing (a heart monitor works best for this, although you could also manually count your heart beats between 12 and 18 seconds after standing up and again between 90 and 120 seconds after standing – and then multiply the number of counted beats by 10 in the first case and two in the second situation to obtain the respective pulse rates). If you use a heart monitor, you should determine AVERAGE heart rate during the period 90-120 seconds after standing up; for example, if your heart rate is 92 beats per minute 90 seconds after standing and 88 beats per minute 30 seconds later, the average 120-second heart rate would be 90.
However, athletes often develop higher than usual standing heart rates shortly before they descend into the overtrained condition, according to Rusko. Usually, the most severe changes are in the 90- to 1 20-second heart rates, which increased by more than 10 beats per minute (from 80 to 90-95) for many of the Finnish athletes who subsequently overtrained. This rise in heart rate wasn’t sudden, however; it often took place over a period of about four weeks, giving athletes ample time to ease back on the training throttle.
Why would such heart-rate accelerations be a warning sign for overtraining? Bear in mind that pulse rate is controlled by the nervous system, and the nervous system is one of the first three systems to show signs of overtraining. Thus, nervous system irregularities show up as changes in heart rate, which you can monitor quite easily, without the need for expensive endocrine or immune-system tests.
Rusko believes that athletes may also want to have a ‘back-up’ system to check their risk of over-training. For example, a cyclist might pedal an exercise bicycle with a somewhat difficult – but submaximal – power output of 225-250 watts for at least 10 minutes every week or so. If fitness is improving, heart rate during this 10-minute exertion should decline over time; if the athlete is on the verge of overtraining, however, heart rate would tend to expand by at least six to eight beats per minute.
Bear in mind that each test – whether it’s Rusko’s orthostatic one or the submaximal exercise procedure – should be done under similar conditions. If an athlete is dehydrated or nervous, or if the environmental conditions have changed from cool and dry to hot and humid or vice-versa, heart rate will automatically change, too, even if there’s no real alteration in the athlete’s training status. Also, remember that another popular heart-rate test – checking one’s pulse rate upon awakening in the morning – has been shown to be an unreliable indicator of overtraining, and it’s not clear yet that Rusko’s orthostatic methods will be totally dependable. As a result, athletes should be very careful with their training; it’s always better to train too little and save one’s maximal efforts for competitions, rather than overtrain.
Overtraining Effects on Hormonal and Autonomic Regulation in Young Cross-Country Skiers,’ Medicine and Science in Sports and Exercise, vol. 26(5), p. S65, 1994