Trench foot
Trench foot can be prevented by keeping the feet clean, warm, and dry. It was also discovered in World War I that a key preventive measure was regular foot inspections; soldiers would be paired and each made responsible for the feet of the other, and they would generally apply whale oil to prevent trench foot. If left to their own devices, soldiers might neglect to take off their own boots and socks to dry their feet each day, but if it were the responsibility of another, this became less likely. Later on in the war, instances of trench foot began to decrease, probably as a result of the introduction of the aforementioned measures; of wooden duckboards to cover the muddy, wet, cold ground of the trenches; and of the increased practice of troop rotation, which kept soldiers from prolonged time at the front.
Barefoot
Since there is no artificial protection of the bare foot, some of the possible issues include cuts, abrasions, bruises, or puncture wounds from glass, nails, rocks, or thorns, as well as poisonous plants, animals, or parasites that can enter the body through the cuts on an injured bare foot. In people who are not habitually barefoot, Athlete's foot is spread by fungal spores coming into contact with skin that has been weakened and made moist. The fungus is known to only affect around 0.75% of habitually barefoot people in one study and can be prevented by reducing shoe use and keeping the feet dry, particularly after walking through a damp environment where people communally walk barefoot as the fungus only develops under the right conditions, such as when people fail to properly dry their feet after swimming or showering and then put on shoes. Wearing shoes such as flip flops or sandals in these areas can reduce the risk. As such, the fungus is very unlikely to develop on a person who goes barefoot all the time.