Updated 05 July 2013

Lack of exercise = lack of energy

Fatigue in children may have many causes. Lack of exercise is one. But why does lack of exercise lead to decreased energy levels?

Fatigue in children may have many causes. Lack of exercise is one.

Unfortunately, this may create a vicious cycle: a child who is tired won't be able to muster up the energy to exercise, and a child who doesn't exercise is at greater risk of suffering from fatigue. And children who don't exercise are at increased risk for disease.

These facts are disturbing if one considers the stats: 45% of South African children don't engage in sufficient vigorous activity during the week, according to the National Youth Risk Behaviour Study (2002).

Possible causes of lethargy
But why does lack of exercise lead to decreased energy levels?

According to Dr Karen Heath from the UCT/MRC Research Unit for Exercise Science and Sports Medicine, possible causes of lethargy in inactive kids could include the following:

  • Regular physical activity increases the red blood cell count. These cells are oxygen carriers. By increasing activity, kids will be increasing their blood flow and consequent oxygenation of cells, which is especially important for the brain. If this doesn't happen, the child's energy levels could suffer.
  • Physical activity increases the amount of glucose transport. An inactive kid may also have a high-calorie diet. Without exercise, the child may experience a form of rebound hypoglycaemia (the blood sugar spikes, only to be met with a flood of insulin, which quickly sweeps the glucose out of the blood and into the cells). The result is a sudden drop in blood sugar, resulting in fatigue and a lack of energy.
  • Lean muscle mass has a direct effect on metabolic rate. The higher the amount of muscle, the higher the metabolic rate. A reduction in physical activity will lead to a reduction in lean muscle mass, which will lead to lack of energy.

Preventing chronic fatigue
Interestingly enough, high activity levels during childhood may also help to reduce the risk of developing chronic fatigue later in life, according to a UK study.

Chronic fatigue syndrome is characterised by extreme disabling fatigue that has lasted for at least six months, is made worse by physical or mental exertion, does not resolve with bed rest, and cannot be attributed to other disorders.

Researchers monitored more than 16 000 children over a period of 30 years, and found that 1,2% of the participants developed chronic fatigue syndrome between the ages of 14 and 30. Those who had been sedentary as children had a higher risk of developing the disease than those who regularly played sport.

What to do

  • Schedule physical activity for times in the day or week when your child is less likely to feel tired.
  • On days when the child is especially weary, try to encourage simple stretching exercises – anything that will encourage him or her to get moving.
  • Convince your child that if he or she gives it a chance, exercise will increase his or her energy levels.
  • Act as a role model – you can't tell your child to go out and exercise while you're sitting in front of the television.
  • Make sure that your child also follows a healthy diet, which includes lots of fruit, veggies, whole-grain foods, legumes, nuts and fish.

- (Carine van Rooyen, Health24)


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