|Caucasians are evolutionarily adapted to cold climates, Africans not. Source: Wikimedia|
Daanen and Van Marten Lichtenbelt report that Europeans differ markedly from other populations in heritable adaptations to cold climates, whereas Africans have marked physiological adaptations to hot climates.
Thus Africans are better adapted to hot climates, as evolutionary theory predicts.
Compared to Africans, Caucasians and Eskimos have higher basal metabolic rates producing more heat, making Africans better adapted to hot climates and Caucasians and Eskimos to cold climates.
Africans have better heat loss capacities than Caucasians, while Caucasians and circumpolar peoples have better heat generating and cold tolerance capacities.
Africans have slower and reduced cold-induced vasodilation compared to Caucasians:
It seems there exist substantial physiological differences between races and these differences arose as specific adaptations to ancestral habitats.