Heat reactions of some Bantu tribesmen in southern Africa

¹ Applied Physiology Laboratory and Mathematical-Statistical Division, Transvaal and Orange Free State Chamber of Mines, Johannesburg, South Africa

Samples of 20 Bantu each from various tribes in southern Africa have been subjected in the late summer in Johannesburg to the established "standard heat-stress test" and were compared with a sample of mixed Bantu, studied in Johannesburg in the late winter. The mean rectal temperatures of the summer group were significantly lower than the mean of the winter group. Heart rates and sweat rates were not different. Intertribal comparisons revealed no significant differences in resting values or in heat reactions. An outstanding feature was that only 3 men of the 120 unacclimatized Bantu reached a rectal temperature of 104 F, and only one collapsed (this is 3% compared to the 50% of Caucasians who did not complete the test). No distinctions can be made between these Bantu tribes in their states of acclimatization in spite of the fact that some came from temperate and others from subtropical regions. The range of climates in the tribal territories is, however, small. Expressed as basic effective temperatures, the January climates—a hot, summer month—vary from 71 to 79 F in these different regions.

Submitted on September 17, 1963