Turning Purple While Running: Causes, Concerns, and What to Do

Why do I turn purple when I run?

Turning purple during a run, while often alarming, is typically a physiological response to changes in blood flow, oxygen saturation, and temperature regulation, but can occasionally signal an underlying health concern.

Understanding Skin Color Changes During Exercise

During strenuous physical activity like running, your body undergoes a complex series of physiological adjustments to meet the increased demands for oxygen and nutrient delivery to working muscles, and to dissipate heat. These adjustments directly impact blood flow and, consequently, your skin's appearance.

Normal Responses:

• Redness (Erythema): The most common observation, caused by widespread vasodilation (widening of blood vessels) in the skin. This shunts more warm, oxygenated blood to the surface to facilitate cooling through convection and radiation.
• Pallor (Paleness): Less common during activity itself, but can occur if blood is significantly shunted away from the skin to the working muscles, or in cases of shock or severe dehydration.

The appearance of a purplish hue, however, points to specific circulatory or oxygenation dynamics that warrant closer examination.

The Science Behind "Purple" Skin During Running

The color of your skin is heavily influenced by the blood flowing through its capillaries. Oxygenated blood, rich in hemoglobin bound to oxygen, appears bright red. Deoxygenated blood, where hemoglobin has released its oxygen, appears darker, often with a bluish or purplish tint.

Key Physiological Factors:

• Peripheral Cyanosis: This is the most direct cause of a bluish or purplish skin discoloration. It occurs when there is a reduction in oxygen saturation in the small blood vessels (capillaries) near the skin surface. While central cyanosis (affecting lips, tongue) is always serious, peripheral cyanosis during exercise can sometimes be a localized, benign response.
• Vasoconstriction in Non-Essential Areas: During intense running, your body prioritizes blood flow to your working muscles (legs, core) and vital organs (heart, brain, lungs). To achieve this, blood vessels in less critical areas, such as the skin of your face or extremities, may constrict (vasoconstriction). If this constriction is significant, it can slow blood flow, allowing tissues to extract more oxygen from the blood before it returns to the heart. This leaves behind more deoxygenated blood in the capillaries, resulting in a purplish tint.
• Increased Oxygen Extraction: Even without significant vasoconstriction, highly active muscles extract a greater percentage of oxygen from the blood flowing through them. This means the venous blood returning to the heart, and passing through superficial veins, will have a lower oxygen content, appearing darker. If this darker blood pools or is visible through the skin, it can contribute to a purplish appearance.
• Cold Exposure: Running in cold weather can exacerbate the purplish appearance. Cold temperatures trigger a natural vasoconstriction response in the skin to conserve core body heat. This reduces blood flow to the skin, increasing oxygen extraction and making any deoxygenated blood more visible.
• Capillary Engorgement and Venous Pooling: In some individuals, particularly in areas like the lower legs or face, superficial capillaries and veins may become engorged with blood due to increased pressure and blood volume during exercise. If this blood is more deoxygenated, it can contribute to a purplish-blue appearance.
• Individual Skin Tone and Capillary Density: People with lighter skin tones or higher densities of superficial capillaries may be more prone to showing these color changes.

Potential Underlying Causes (When to Be Concerned)

While often a normal physiological response, persistent or symptomatic purple discoloration can sometimes indicate an underlying issue.

• Cardiovascular Issues: Conditions affecting the heart's ability to pump blood efficiently (e.g., heart failure, valvular disease) or problems with blood vessel function can lead to poor circulation and reduced oxygen delivery, causing cyanosis.
• Respiratory Issues: Lung conditions (e.g., asthma, COPD, pneumonia) that impair oxygen uptake can result in systemic hypoxia, leading to a more generalized purplish discoloration.
• Anemia: Severe anemia (low red blood cell count) means less oxygen-carrying capacity, which can contribute to signs of hypoxia, though pallor is more common.
• Polycythemia: An abnormally high red blood cell count can sometimes give the skin a ruddy or purplish appearance due to the sheer volume of blood cells.
• Raynaud's Phenomenon: This condition causes episodic vasoconstriction, typically in the fingers and toes, in response to cold or stress. While often affecting extremities, it can sometimes manifest in other areas.
• Dehydration: Significant dehydration reduces blood volume, making the circulatory system less efficient and potentially exacerbating issues related to blood flow and oxygen delivery.

When to Seek Medical Attention

It's important to distinguish between a benign, transient purplish hue and a potentially concerning symptom. Consult a healthcare professional if you experience "purple skin" during running accompanied by any of the following:

• Shortness of Breath: Especially if it's disproportionate to your exertion level, or if you struggle to catch your breath after stopping.
• Chest Pain or Discomfort: Any pain, pressure, or tightness in the chest should be immediately evaluated.
• Dizziness, Lightheadedness, or Fainting: These are signs of inadequate blood flow to the brain.
• Extreme Fatigue or Weakness: Beyond what's expected for your activity level.
• Numbness, Tingling, or Coldness: Especially in the extremities, which could indicate poor circulation.
• Discoloration that is Persistent: If the purple color doesn't resolve quickly after you stop exercising and warm up.
• Localized Pain or Swelling: If the discoloration is confined to one area and accompanied by pain or swelling.
• A History of Heart or Lung Conditions: If you have pre-existing conditions, any new or worsening symptoms should be discussed with your doctor.

What You Can Do

If you experience purple skin during running and have no concerning symptoms, consider these strategies:

• Stay Hydrated: Ensure adequate fluid intake before, during, and after your runs to maintain optimal blood volume and circulation.
• Proper Warm-Up: A thorough warm-up gradually increases blood flow to muscles and prepares your cardiovascular system, reducing the sudden shock to the system.
• Gradual Progression: Avoid sudden increases in intensity or duration. Allow your body to adapt progressively to new demands.
• Dress Appropriately: In cold weather, layer clothing to maintain core body temperature and protect exposed skin.
• Listen to Your Body: Pay attention to how you feel. If you're pushing too hard, scale back.
• Cool-Down: A gradual cool-down helps normalize blood flow and heart rate, preventing blood pooling.

Conclusion

Observing a purplish tint to your skin while running can be a noticeable, and sometimes unsettling, physiological phenomenon. For many, it's a benign consequence of the body efficiently shunting blood, extracting oxygen, and regulating temperature under exertion, especially in cooler conditions. However, the expert runner and fitness enthusiast understands the importance of distinguishing between normal physiological responses and potential warning signs. If the discoloration is accompanied by other concerning symptoms or is persistent, it is always prudent to consult with a healthcare professional to rule out any underlying medical conditions. Prioritize listening to your body and seeking expert advice when in doubt.