Oct. 5, 2004 -- Physical activity is vital for children for many reasons, from reducing obesity to building healthy fitness habits. Now, British researchers have added another benefit to the list: Active kids are less likely to develop chronic fatigue syndrome later in life than their sedentary childhood peers.
Chronic fatigue syndrome is a disabling condition characterized by severe fatigue that lasts at least six months that does not significantly improve with rest. It's not a side effect of other health problems, and it must be severe enough to interfere with daily life to qualify for formal diagnosis.
Its causes are not known.
However, several risk factors have been identified, including being female; birth order; psychological problems in childhood or in a patient's mother; stressful events; obesity; high academic ability; high levels of exercise; infections; and atopy (a group of conditions such as asthma, eczema, or seasonal allergies caused by a specific type of immune system disorder), among others.
Those theories associated with childhood were investigated by Russell Viner, honorary senior lecturer in adolescent medicine at Royal Free and University College Medical School in London; and Matthew Hotopf, professor of general hospital psychiatry at London's Institute of Psychiatry.
They studied data on more than 16,000 people born in England, Scotland, and Wales in 1970. Participants were contacted at ages 5, 10, 16, and 29-30 years.
Their mothers, teachers, and school doctors provided demographic information and input on the children's psychological health, physical activity, academic performance, obesity, and severe or prolonged illnesses.
The mothers also completed questionnaires about their own mental health.
Around age 30, participants told researchers whether they had ever had chronic fatigue syndrome. At that point, the study had about 11,000 participants.
Less than 1% reported ever having chronic fatigue syndrome. None said they had had it before age 10, and only two reported its onset before age 16. Forty-eight participants said they were currently affected by the condition.
Participants who had ever experienced chronic fatigue had several common characteristics that had previously been identified as risk factors for the disease.
They were more likely to be female; members of a high social class as children; and survivors of limiting, longstanding childhood medical conditions.
The findings also contradicted other suspected risk factors.
For instance, children who got a lot of exercise were less likely to develop chronic fatigue syndrome later on. That directly defied an earlier theory that high exercise levels were a risk factor for the condition.
"The most sedentary children were at the greatest risk," write the researchers in the online journal BMJ Online First.
Psychological problems in mothers or kids were not risk factors. Nor were academic ability, birth order, birth weight, obesity, parental illness, and atopy.
The study relied on participants' self-reports of chronic fatigue syndrome. Future research could be helped by confirming diagnoses, say the researchers.