Among chronic exercisers, there is always the potential of doing more but receiving less. What many exercisers do not realize is that additional workouts can sometimes lead to the law of diminishing returns, where anticipated responses do not occur. It has been well established that in order to receive a training effect, the exerciser must experience some fatigue. This fatigue will in turn induce a need for recovery, which leads to a period of overcompensation or the training effect. However, if there is little or no recovery, combined with additional intense activity, the overcompensation or training effects do not occur, and overtraining symptoms can be observed. The term overtraining has been used interchangeably with staleness, burnout, chronic fatigue, stagnation, overwork or run down. Researchers have reported no less than 31 features of overtraining extending to 84. The most prominent features of overtraining include: heavy legs, sore muscles, high resting heart rate, poor motivation, sleep disturbances, low libido, frequent sickness or infection, weight loss, depression and increased rating of perceived exertion.
- Impaired Pituitary Hormonal Response to Exhaustive Exercise in Overtrained Endurance Athletes, Urhausen, A. , Holger, H. W. G. , & Kindermann, W. (1998), Medicine and Science in Sports and Exercise 30 (3): 407-414
Overtraining literature has recommended measurements of substrates in peripheral blood to predict when athletes are approaching or are in the overreaching or overtrained state. An additional diagnostic method has now been suggested with the monitoring of blood hormones. This has been supported by the observation that cortisol and testosterone amounts change with the fluctuations in training intensities and volumes. Changes in the hormones regulated from the hypothalamus, pituitary, adrenal and gonadal glands appear to play a significant role in the symptoms of overtraining.
The purpose of this study was to investigate the hormonal and biochemical responses of overtrained endurance athletes for a period of 1. 5 years of rest and exercise.
Seventeen male endurance trained cyclists volunteered for this study. Subjects were tested on a bicycle ergometer on short-term high intensity bouts at 10 percent above the anaerobic threshold. Subjects were tested every three to five months over two separate days. For a couple of weeks prior to some of the testing days, subjects were asked to train at additional high intensity sessions to induce an overtrained state. Tests included: anthropometric measurements, incremental graded exercise test, maximal anaerobic cycle ergometer test, urine samples, capillary blood samples to measure lactate, glucose, epinephrine and norepinephrine, ferritin, urea, creatine, lactate dehydrogenates, testosterone, cortisol, growth hormone and insulin.
During the overtrained state there was a significant reduction in performance (27 percent) on the test to exhaustion. Epinephrine and norepinephrine levels did not change significantly in the overtrained period. A lower maximal exercise, induced increases in adrenocorticotropic hormone and growth hormone were reported. There was also a decrease in cortisol and insulin in the overtrained. Urea, uric acid, ferritin, and the activity of creatine kinase showed no difference across conditions.
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- Subjects in this study continued to complain about overtraining symptoms for at least 10 days after the tests. This would indicate a short term or beginning overtraining or more over an overreaching condition.
- This study further supported the influence of high intensity training above the anaerobic threshold as the main precursor to reaching overtraining. From this type of training, subjects complained of heavy feelings in the legs, increased perception of effort, chronic fatigue during the day and sleep disorders. The heavy feelings experienced occurred without an increase in lactate levels, indicating the cause could be possibly due to the desensitizing of the chemoreceptors in the body.
- The reduced levels of growth hormone, cortisol and insulin as regulated by the pituitary gland can have a detrimental affect on glycogen and protein re-synthesis during recovery. This may lead to a reduced performance due to the inability of the body to utilize carbohydrate, leading to an increased reliance on fat as a main source of fuel.
- Other studies have reported that changes in urea, glucose, creatine, creatine kinase, and ferritin are reliable indicators of overtraining. Increased urea concentrations indicate a greater utilization of protein as a fuel source, increase in uric acid indicates stress on the ATP supplying system and lower levels of ferritin indicate a decreased iron store. Perhaps there were not significant changes within this study, due to the nature of the overtraining induced. As the method of overtraining reported here was more an overreaching, perhaps it was not severe enough to elicit the changes reported in other studies. Conversely, the hormonal changes that occurred from the pituitary and hypothalamic regions could be good indicators of the early onset of overtraining or overreaching.
- Overtraining: Consequences and Prevention, Eichner, R. (1995), Journal of Sports Sciences. 13: S41-S48
Overtraining has been known as overreaching, staleness, burnout, overwork, chronic fatigue, stagnation or rundown. It implies that more training does not always produce better results. Overtraining can be characterized by muscle damage, cytokine actions, hormonal changes, neurotransmitter, hematological and immune changes, mood swing and nutritional problems.
The purpose of this study was to review the consequences of overtraining and suggest some preventative measures to avoid it.
It is well reported that strenuous exercise can cause muscle damage. This can be seen by an increase the muscle proteins of myoglobin and creatine kinase in the blood. Marathon runners have demonstrated muscle damage in the form of fiber necrosis and inflammation for the week following the race. The muscles continue to repair for the next week and then slowly regenerate for the next 10 to 12 weeks. It has even been shown that marathoners before the race have some muscle damage from the previous months training. This same response has also been reported in swimmers and rowers and those exercising in an eccentric mode. One problem associated with muscle damage after exercise participation is the perception that the muscles are recovered, when in fact they are still damaged. The condition can be compounded by additional workouts, through extra stress taken up by the muscle, tendons, ligaments, joints and bones. The continual stress can activate an acute phase of reaction, where neutrophils and monocytes (white blood cells released to fight infection) release cytokines (antibodies and antigens) to help repair the damaged tissue. Lymphocytes are also released which will cause a mild fever encouraging rest and time to heal.
Many exercisers have felt the effect of eccentric exercise and the discomfort it causes. With this comes the potential for glycogen depletion and impairment of glycogen re-synthesis. This is partly caused by the muscles insensitivity to insulin, which will blunt the muscle’s ability to take up glycogen. It has been reported that there is a strong relationship between glycogen intake, muscle damage and overtraining. Invariably athletes who overreach without a concomitant increase in carbohydrate intake can be predisposed to overtraining. Unbelievably some athletes do under fuel and place themselves in a potential overtrained state from the very beginning.
Many researchers have identified mood changes as a way of monitoring overtraining. Self-scored mood scores (POMS) show how athletes rate themselves against criteria that measure mental health. High scores are generally attributed to vigor and low scores for tension and depression. It does appear that athletes do develop a “dose related mood disturbance”, where mood does deteriorate as the training becomes harder and more frequent. It has been reported that a person’s mood changes dramatically with overtraining. The POMS has been reported to change with as little as three days of increased training. Consequently, monitoring mood changes through POMS may identify overtraining in its early stages.
Researchers for many years have attempted to predict overtraining through monitoring specific hormonal levels. While this has shown some promise, there are many questions as to its validity. Hormones studied have shown varying responses in different trained states, leading to many inconclusive recommendations. An example of these inconsistencies is with the plasma testosterone / cortisol ratios. It has been shown that testosterone levels fall, remain the same or are of little use to females in overtrained runners, rowers, swimmers and biathletes. Other than overtraining, this fall can also occur during fatigue, lowered libido, low sperm count or function.
Researchers have reported anywhere between 31 to 84 features of overtraining.
The 10 most prominent overtraining symptoms for the runner includes: heavy legs, sore muscles, high resting heart rate, poor motivation, sleep disturbances, low libido, frequent sickness or infection, weight loss, depression and higher perceived exertion.
To effectively prevent overtraining, athletes must be monitored on an individual basis. Just as training programs should be individualized so to should overtraining. Mood monitoring appears to be popular with a combination of fatigue and soreness. The athlete must also be responsible for keeping training diaries logging in thoughts and feelings. Blood tests measuring creatine kinase may be worthwhile, as would performance tests.
- Short Term Changes in Blood Leucocyte and Platelet Count following Different Durations of High Intensity Treadmill Running, Gleeson, M., Blannin, A. K., Sewell, D. A., & Cave, R. (1995), Journal of Sports Sciences. 13: 115-123
Leucocytes are white blood cells whose main function within the body is to combat disease and infection by phagocytosis (neutrophils) or the creation of antibodies (lymphocytes). Phagocytosis is a process where the white blood cell ingests the invading bacteria and dispose of the remaining matter. During different form of exercise up to 60 minutes, there is an increase in the number of circulating leucocytes. The number of leucocytes released and remaining after exercise is affected by the intensity and duration of the exercise. The increase in leucocytes is due to their release from the internal vascular walls. It has been reported that the higher the intensity of the exercise, the longer the leucocytes will remain in the system.
The purpose of this study was to investigate the effect of high intensity training on the post exercise levels of leucocytes and plasma volume.
Eight active subjects volunteered for this study (six males and two females). On separate testing days and after a warm up, subjects ran on a treadmill at 20 km. h-1 for 30, 60, 90, 120 or 150 seconds or to fatigue. One duration workload was tested every week until all were completed. Blood samples were taken before the test, immediately after test and 5 minutes post test. Blood parameters measured included lactate levels, hemoglobin, cell volume, red blood cell count, platelet count, and leucocycte count.
Maximum heart rate was recorded within approximately 30 seconds of the exercise. At all levels of intensity there was an increase in leucocycte count peaking at 60 seconds duration post exercise period. There was also a significant increase in leucocytes during the post exercise period after exercising to exhaustion.
The increase in post exercise leucocytes was mainly due to increases in lymphocytes and neutrophils. At exhaustion, plasma volume of the blood decreased by approximately 16 percent compared to the beginning of the test. After five minutes of recovery, the leukocyte count fell significantly after 30 and 60 seconds duration, remained unchanged for the 90 and 120 seconds duration and increased for the 150 seconds to exhaustion. This increase was almost exclusively due to the increase in the number of circulating neutrophils.
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- Many researchers have reported an immuno-enhancing effect from participation in mild moderate exercise. While it has been suggested that athletes who train hard and long, can experience an immuno-suppressing response and be more prone to infection. Those that engage in overtraining programs could possibly face an increase susceptibility to infection and sickness.
- It may be that the leukocyte responses after exercise differ depending upon the type and intensity of exercise. In long distance duration training (marathon), there is generally a significant increase in the number of circulating neurophils, with only a small increase in the number of lymphocytes. Neutrophils have the responsibility of combating infection through the activity of phagocytosis. Phagocytosis occurs through the neutrophils actively pursing bacteria by ingesting the irritant and removing the debris. The neutrophils also release lysosome enzymes, which destroy certain bacteria. Neutrophils are the most abundant white blood cells in the body. In this study, which focused on high intensity exercise, the leukocyte response was different. Rather than an increase in neutrophils, there was a significant increase in lymphocytes. Lymphocytes (B cells, T cells and killer T cells) are engaged in the production of antibodies. An antibody reacts with an antigen (e.g., toxins released by bacteria), which will seal off the bacteria and stop it from coming into contact with other chemicals in the body. These responses are very specific, as only certain antibodies will react with certain antigens. If this response occurs in high intensity exercise, it would seem possible that in lower intensity prolonged exercise there is a redistribution of lymphocytes to storage compartments, due to the action of the steroid cortisol hormone.
It could then be concluded that higher intense exercise can produce significant increases in leucocytes immediately after exercise and well into recovery. It also showed that the longer the duration of the intense exercise, the greater the magnitude of the leukocyte increase. Given that high and low intensity exercise appears to produce different types of leukocyte (immune response) responses, it may be possible that susceptibility to sickness during training could be related to the type of infection and the inability of the body to fight it according to the differing immune capabilities of the neutrophils or lymphocytes. Perhaps illnesses associated with overtraining could be different according to whether the overtraining was caused by high intensity exercise or low intensity long duration exercise.
- This study reported an increase in platelet concentration immediately after exercise and after five minutes of recovery. A platelet is a thrombocyte (type of leukocyte), which is shaped like a disc and provides for blood clotting.
- The increase in leukocyte activity after intense exercise has been attributed to an increased release from the walls of the blood vessels, as well as an increased release from the liver and spleen. This increased release of leucocytes is reportedly due to the increased blood flow during exercise and the increased concentration of epinephrine and norepinephrine hormones. These hormones are responsible for increases in blood pressure, heart rate, constricts vessels, decrease rate of digestion etc.
- During bouts of intense exercise, there is a significant increase in the amount of circulating lactate and associated hydrogen ions. Lactate levels generally peak at approximately three to five minutes post exercise. It is at this time, that the pH of the body drops considerably and becomes more acidic. During this acidosis it has been reported that platelet and leucocytes lose their adhesiveness to the vascular walls and are released into the circulatory system.
- Mood States as an Indication of Staleness and Recovery, Hooper, S., Traeger Mackinnon, L., & Hanrahan, S. (1997), International Journal of Psychology. 28: 1-12
To recognize overtraining in the athlete it has been suggested that a continuum of stages from staleness to overtraining be recognized. Regardless of the stage, all are characterized by a decrement in performance. Sport scientists are still unable to totally agree on the physiological markers that trainers or coaches can use to identify the overtrained state. However, some success has been reported in identifying overtraining through mood assessments via the Profile of Mood States and the Total Mood Disturbance Scores. The reliability of these assessment tools in identifying when an athlete is suffering from staleness or overtraining as evidenced by changes in tension, depression, anger, vigor, fatigue and confusion is still open to question. It has been suggested that mood changes can be significantly affected by bouts of intense training. However, during tapering or reduced workload periods, the mood disturbances do not return to pre intense training levels.
The purpose of this study was to measure mood states as demonstrated by changes in tension, depression, anger, vigor, fatigue, confusion over an entire season between stale athletes and those who are intensely trained.
Nineteen male and females swimmers were evaluated by the Profile of Mood States five times during a six months season. They were tested during the early, mid and late season, prior to the tapering period and then directly after major competition. All swimmers monitored their training in daily training logs and were supervised by personal coaches.
The subjects demonstrated inconsistencies in POMS scores between those that were classified as stale and non-stale throughout the season. Some of the POMS scores did correlated highly with exercise intensity, but not with the volume of training reported. The results indicated that stale athletes did not necessarily demonstrate mood scores that were different from non-stale athletes.
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- The POMS method used to assess staleness appears useful when it is considered that symptoms typically manifest themselves as depression, anxiety, irritability and performance decrements. POMS measures appear to change when athletes are subjected to intense bouts of training. However, whether the POMS scores obtained can predict staleness is still open to question.
- The results of the POMS scores over the season appeared to show little difference. Scores obtained during the season were little different from those obtained during the taper period. Whilst the training load was reduced during the taper, the intensity remained high. Perhaps the POMS scores were more closely related to intensity rather than volume. Another reason given was the increased psychological stress associated with the taper, recognizing the competition was close at hand.
- While there is some conjecture as to the validity of using mood change tools for predicting staleness, the strength of their application may be the initial identification of those athletes “at risk” who have the potential for staleness or overtraining. In the event of a trainer consulting with a client who has a propensity to overtrain, a POMS assessment may provide an objective view for the client to consider.