Stress takes its toll on kids with asthma, more than quadrupling their risk of having an asthma attack.

And it doesn't take long, the chance of having an asthma attack climbs within 48 hours of a stressful event, according to a new study.

The aftereffects of stressful events rev up again about six weeks later, nearly doubling the risk of an asthma attack, say the researchers, who included Seija Sandberg of the mental health sciences department at London's University College.

Sandberg and colleagues studied 60 children aged 6-13 in Glasgow, Scotland, who had asthma for at least three years.

The study focused on severely negative life events that would seem threatening, upsetting, or unsettling to most children of the participants' age.

Examples include births, changes in family relationships, major traumatic events, separations from family, illness, and hospitalization.

Within two days of a stressful life event, the kids' risk of an asthma attack more than quadrupled.

The heightened risk might be due to inflammatory and airway responses triggered by a combination of hormones, brain chemicals, and the response of the nervous system to stress, say the researchers.

The initial risk subsided within three to 10 days, but that wasn't the only consequence of stress.

Five to seven weeks after the stressful event, the risk of asthma attack rose again. This time, it nearly doubled.

It's tougher to explain the delayed stress reaction, but the researchers speculate that the effects of stress on the immune system might be at work.

While stressful events can't always be avoided, parents should be aware that such situations can affect kids with asthma. Talk to your child's doctor to see what signs you should look out for. And know how you should respond in case your child has breathing problems or other symptoms of an asthma attack.