Bathing: As it turns out, showering or bathing daily, while it may make us more socially acceptable, wreaks havoc on something hilariously called the horny layer. Hot water, soap and abrasive surfaces strip off the horny layer, exposing living cells to the elements. Damaging this protective layer of skin makes us more susceptible to disease. Before recent modern conveniences, people bathed less often, and frequently in the same water. The most important thing to do to keep the skin healthy is to preserve the horny layer. There’s no magic number of showers each week, though it’s generally agreed that the number would fall somewhat shy of seven. Skipping showers gives your skin time to repair some of the damage that the last shower caused.

Sleeping: The idea that an uninterrupted eight hours is the only sleep pattern natural to mankind is surprisingly recent. Before someone who wasn’t Thomas Edison invented the light bulb, people in areas with more than eight hours of darkness usually slept in segments: three to five hours of sleep, an hour of wakefulness and then another three to five hour nap. The hour or so of awake time was used for quiet reflection, sex, smoking and pretty much everything except staring at the wall terrified of insomnia.

Breathing: When upright, most people are habitual chest breathers: We use a shallow form of respiration that makes use of only the top part of the lungs. In reality, most of the blood vessels that take up oxygen are in the bottom, neglected half. Since so much lung power is going to waste, we get less oxygen, and as a result, we’re all breathing more rapidly than nature intended us to. It turns out that breathing is one area in which babies are much smarter than you. Babies use a deeper type of respiration called abdominal breathing, which strengthens and makes full use of their diaphragms. It’s only as we grow older that we revert to the more inefficient style. Luckily, you can train your body to go back to breathing properly, and over time, you can even breathe abdominally in your sleep. To practice it, try to “inflate” your stomach as you breathe in, while keeping your chest relatively still. Then contract your abdominal muscles on the exhale. Not only will this give you more oxygen per breath, it will eventually strengthen the diaphragm. A stronger diaphragm means you get more oxygen with each breath, so your brain won’t need to divert any away from your muscles, meaning that you get tired less easily.

Pooping: A 2003 study observed 28 people pooping in three positions: sitting on a high toilet, sitting on a lower one and squatting like they were catchers at a baseball game. The researchers found that pooping took about a minute less when done squatting and that participants rated the experience as “easier.” In fact, toilets that require you to squat that way have been the standard for most of human history and are still widely used in the non-Western world.