Fainting

Circulatory System

If the brain lacks oxygen for even a moment, a temporary loss of consciousness or fainting will result. Danger signs that serve as warnings include visual blurring, light-headedness, dizziness, noticeable weakness, sweating or nausea. Often fainting serves a purpose – it allows the body to recover by increasing the supply of blood to the brain.

A person who has just fainted should lie still for some time to let the body recover. Fainting can also be a sign of low blood sugar levels combined with a temporary circulatory imbalance. It is often related to low blood pressure, and an over-burdened venous system – standing for long periods, heat, dehydration, and stress all cause the circulatory system to become sluggish and slow. Other origins include sudden fear, anxiety, and physical activity that changes breathing patterns, causing an improper oxygen exchange.

Fainting can also be a protective response from the body to intense pain from an injury. Recurring fainting should be investigated for an underlying cause.