The biological payback for upright walking in humans can be considered …

Due to the ability to walk upright, a number of physiological changes develop in humans, which proves that in the process of evolution there was little time to improve the body. The first thing that affects upright walking is pain in the vertebra, namely in the lumbar spine. Throughout the day, a person’s height decreases by several centimeters, since it decreases due to the S-shape and load. The veins of the lower extremities also suffer, which, with age, gives rise to the prerequisites for the development of varicose veins.