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18 September 2006

The high toll of overtraining

Two-time Comrades winner Lindsay Weight, who died last Tuesday, had a history of overtraining. Health24 takes a look at the risks.

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The death of two-time Comrades winner and sports scientist Dr Lindsay Weight sent shock waves through South Africa's running community.

An investigation into the cause of her death is currently underway, and post-mortem results should be available later this week.

Die Burger reports that Prof Tim Noakes, director of the UCT/MRC Research Unit for Exercise Science & Sports Medicine and former colleague of Weight, was well aware of the fact that she had a history of overtraining. In fact, in his book Lore of Running (2001), Noakes uses Weight as an example in a chapter on the subject.

Weight was training for the Iron Man Competition when she died.

Health24 investigates the risks of overtraining:

Overtraining: the basics
Overtraining is exercise beyond the body's ability. It's when training intensity or duration surpasses the recuperation time being offered to the body.

A long-distance runner who goes out and runs hard every day, perhaps for several hours, and allows no time for recuperation, is probably overtraining.

Common signs and symptoms of overtraining include:

  • dwindling enthusiasm for working out;
  • increases in resting heart rate and resting blood pressure;
  • muscle or joint soreness that won't go away;
  • changes in the menstrual pattern;
  • increased incidence of colds and infection;
  • a decrease in appetite and weight;
  • disturbed sleep;
  • increased irritability, anxiety or depression.

"Overtrained runners find that while their minds are ready to run, their bodies would much rather be asleep in bed. And the more their minds force them to train, the more their bodies resist until, in the race, the body has the final say," Noakes writes in Lore of Running.

The effects on the body
Noakes points to the following physiological changes that take place in the body:

  • Histological changes in muscle, including evidence of muscle fibre and mitochondrial abnormalities. In athletes who suffer from impaired athletic performance after years or decades of heavy training, there may also be alterations in the genetic material of the exercised skeletal muscles, suggesting that those muscles have a reduced capacity to respond to the stress of exercise, repair damage after exercise, and tadapt to training.
  • Reduced capacity of the brain to recruit the muscles used in the activity for which you are trained.
  • Impaired capacity of the hypothalamic-pituitary-axis to mount the normal hormonal response required to adapt to any external stress, including daily heavy training.
  • Reduced sympathetic nervous system activity both at rest and during exercise.

From the above, it is clear that the so-called "overtraining syndrome" can have serious debilitating effects on the body. When overtraining is severe, it can lead to a higher rate of infection, hormone depression, mood disorders, fatigue and restlessness

Research also suggests that women who run long distances are at risk of lower bone density, which can lead to osteoporosis. The more a woman runs, the greater her chance of low bone density.

However, there isn't sufficient evidence to suggest that overtraining per se can lead to sudden death.

Overtraining in Weight's words
In Lore of Running, Lindsay Weight poetically describes how overtraining affected her:

"Science has never really explained to me why on some days I can fly and others are just dead space. Why I can get to the start of a race in the best shape of my life and crumble before half way. Why personal bests happen when you least expect them. Why running connects me to the soul of the universe. And why now, I cannot do what I used to do.

"Maybe I have led a reckless life and squandered my precious life force? I could live with my extravagance if all those miles had been good ones, but many of them were just the endless foot slog of a neurotic fixated on her logbook. Oh to trade any number of those unnecessary miles for the vitality to enjoy my now relatively limited opportunities to run. Can it really be all gone? Why didn't anyone tell me it wouldn't last forever?"

Factors sometimes associated with overtraining
Overtraining and eating disorders, such as anorexia nervosa (AN) and bulimia nervosa (BN) often go hand in hand.

When someone's body mass index (BMI) drops to below 15, his or her health is seriously compromised. The patient's heart is one of the vital organs that can be affected.

Registered dietician Gina Stear explains why: when the body is deprived of energy in the form of food over an extended period, it starts to utilise the muscles for energy. The skeletal muscles will first be targeted, then the fat stores and then the organ muscles, such as the heart muscle. When the heart muscle is compromised, it won't be able to function optimally anymore.

"If someone actively suffers from anorexia, death from heart failure can occur in severe cases," Stear says.

A popular textbook widely used by dieticians confirms this. According to Krause's Food, Nutrition and Diet Therapy: 10th Edition, "Cardiovascular complications have been associated with death in AN. Death from congestive heart failure may occur in AN patients of any age."

Anorexia nervosa is an eating disorder characterised by an intense fear of becoming fat, leading to self-starving behaviour.

A life-long problem
Stear notes that an eating disorder is usually a life-long problem, and that many patients experience "ups" and "downs" throughout their life, depending on their mental, physical and emotional condition.

"Patients who actively want to make the relevant lifestyle changes usually get to a point where they're okay," Stear says. "These patients manage to get to a level where they're able to survive, but they can still suffer mentally, even though, on a physical level, they're not knocking on death's door."

About 50% of anorexic people get back to their normal weight, but almost half of them continue to suffer from other symptoms such as depression, anxiety or difficulty with close interpersonal and familial relationships.

According to Stear, most patients never manage to overcome their eating disorder completely. "Those who do, tend to be in the minority. These people have acknowledged that they have a condition which needs help. They have made a conscious decision to help themselves."

"Bulimics are more likely to get over it in the long term, as they generally tend to be less obsessive. But (their eating patterns) may always be a weak point," she says.

The hearts of patients who suffer from BN can be affected in another way: due to frequent vomiting or the irresponsible use of laxatives, the patient's body can be deprived of electrolytes, such as the minerals magnesium and potassium. These minerals are crucial to the proper functioning of the heart, Stear says.

Other organs affected
Apart from the effects on the heart, AN can also adversely affect the gastrointestinal tract, the central nervous system, the kidneys, and the bones.

The growth and development of children and adolescents with AN can be severely affected.

BM can have equally serious consequences.

- (Health24, September 2006)

 
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