Pulmonary function and exercise responses in relation to body composition and ethnic origin in Trinidadian males

Abstract

1. Indices of lung function, body muscle, levels of habitual activity and the cardiorespiratory responses to exercise were measured in thirty young adult Trinidadians of African, East Indian and European descent. The measurements were made at sea level at a mean temperature of 27 °C, 78 % humidity. The results are compared with those for men of European descent studied by identical methods at Leeds, U. K. (mean temperature 21 °C). 2. The lung volumes and ventilatory capacities of African and Indian Trinidadians were lower than those for Europeans even after standardization for age and height. Tidal volumes during exercise and breathing CO2 were smaller and the maximal exercise ventilation was a higher percentage of individual’s maximal breathing capacity. Ventilation and cardiac frequency were higher in the Africans and Indians than the Europeans during submaximal exercise, but these differences disappeared when the smaller body muscle of the Africans and Indians was taken into consideration. 3. The cardiac frequency during maximal exercise was similar in all groups but the maximal oxygen up take was less for African and Indian Trinidadians than for Leeds men, with the European Trinidadians intermediate. Allowance for body muscle eliminated the difference in maximal oxygen uptake (Vo₂max) between the groups of Trinidadians though within the groups the Vo₂max still correlated with habitual activity. The average Vo₂max standardized for muscle' in the Trinidadians was lower than that for the Leeds me by about 0.7 1. 4. It is concluded that while ethnic factors contribute to ventilatory capacity and tidal volume these are unimportant determinants of maximal oxygen up take compared with habitual activity, environmental temperature and factors which influence body muscle.