Blood rises to the skin's surface in several situations, most notably during instances of bleeding under the skin and in response to physiological changes like exercise.
Bleeding into the Skin
Bleeding into the skin occurs when blood vessels break. This can manifest in various ways:
- Petechiae: Tiny red dots resulting from broken blood vessels.
- Purpura: Larger, flat areas of blood pooled under the skin.
- Ecchymosis: A large bruise, also known as a contusion, resulting from many capillaries breaking close together and blood pooling under the skin's surface. [Source: Cleveland Clinic, Medical News Today, Mount Sinai]
These conditions can be caused by a variety of factors, including trauma, certain medical conditions, or medications. [Source: Cleveland Clinic, Medical News Today, Mount Sinai, Healthline]
Increased Skin Blood Flow During Exercise
During physical exertion, especially in warm environments, blood flow to the skin increases significantly. This is a crucial mechanism for thermoregulation; it helps to dissipate heat from the body, preventing overheating. [Source: PubMed - Physical training and the control of skin blood flow, PubMed - Changes in the control of skin blood flow with exercise training, PubMed - Mechanisms of control of skin blood flow during prolonged exercise] Increased skin blood flow contributes to the overall demands on cardiac output. [Source: PubMed - Changes in the control of skin blood flow with exercise training] Staying hydrated is crucial to maintaining sufficient blood volume, facilitating this increased flow. [Source: NHS Blood Donation]
Skin Blood Color and Appearance
The amount of oxygenated blood in the skin also affects its color and appearance. Individuals may consciously increase skin blood flow (and the amount of oxygenated blood) to optimize their appearance. [Source: PubMed - Skin Blood Perfusion and Oxygenation Colour Affect Perceived]
