Ventilatory capacity if healthy Chinese children: relation to habitual activity.

Ventilatory capacity, including forced expiratory volume (FEV 1-0) and forced vital capacity (FVC), and selected anthropometric indices have been obtained for 36 boys and 19 girls aged 5-10 years from a working class district in Kowloon. The ventilatory capacity is related to stature and is 13 per cent larger for boys than girls. After allowing for stature and sex the residual variation is significantly reduced by also allowing for the children's habitual activity. The ventilatory capacity of the more active children, including those who have lived all their lives in squatter huts on the hillsides, is on average 8 per cent larger than for the inactive children including those who have lived all their lives in tenement flats with lifts. The groups are apparently similar with respect to income, dietary pattern, intelligence and disease incidence, so that findings provide independent support for the hypothesis that the level of habitual activity during childhood contributes to the ventilatory capacity. The absolute level of ventilatory capacity resembles that of Nepalese children and differs from that of some other groups.