Interesting point, as this is actually the topic of some debate. The position you're referring to is known as the Trendelenburg Position. The benefits were tho

Interesting point, as this is actually the topic of some debate. The position you're referring to is known as the Trendelenburg Position. The benefits were thought to lie not so much with increasing perfusion to the brain, but bringing more blood back to the heart (known as preload), thereby increasing cardiac output and increasing blood flow to vital organs. If you're interested in this, there's some neat physiology called the Frank-Starling law [0]. However, it turns out that in practice, cardiac output doesn't actually improve. In fact, this position also increases the risk of fluid build up in the lungs (pulmonary oedema) and can worsen cerebral perfusion [1]. Therefore, it's falling out of favour in the context of shock. A compromise might be to elevate solely the legs, but its efficacy is also being questioned. This illustrates a recurring theme in modern medicine; the human body & disease is so complex and poorly modelled, that it's often not possible to translate intuition or first principles of physiology into treatment. Instead, one relies on real world studies like those reviewed in [1] - AKA 'evidence-based medicine'. [0] https://en.wikipedia.org/wiki/Frank%E2%80%93Starling_law https://en.wikipedia.org/wiki/Frank%E2%80%93Starling_law [1] https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S1481803500008915 https://www.cambridge.org/core/services/aop-cambridge-core/c...