Approximately 7 million years ago (Mya) in Africa, humans separated from their common ancestor, the chimpanzee, and began to walk upright and bipedally in the forests. Approximately 4 Mya, humans migrated to the savannah, where they walked on stable bipeds and were able to freely use their hands. Approximately 2 Mya, humans adapted to the hot-dry environment by shedding their fur and increasing their eccrine glands to prevent hyperthermia during prolonged hunting. They began eating roasted meat, which allowed their brains to grow. After two exoduses from Africa, they adapted to darker and colder environment by changing their skin color and body shape. Modern humans (Homo sapiens) were born in Africa approximately 0.3 Mya, and then migrated around the world. They live worldwide because of their biological (physiological and morphological) and cultural adaptations (such as clothing, housing, and air-conditioning). It is highly unusual for a single species to be distributed throughout all thermal environments on Earth. Humans have overcome harsh natural environments with the power of science and technology, gradually expanding their range of survival and creating more comfortable artificial environments. However, artificial thermal environments can have various adverse effects on health. In addition, recent global warming is predicted to make the Earth’s thermal environment more severe. It has been pointed out that the current advanced artificial thermal environment may hinder the development of human potential and lead to the accumulation of unfavorable qualities. The thermal adaptation problems have been one of the main research topics in physiological anthropology. Environmental ergonomics has also been studied using artificial climate chambers with a focus on human comfort, health, and performance in thermal environments.