What Causes Varicose Veins? 9 Common Risk Factors
Varicose veins develop when the one-way valves inside your leg veins weaken and let blood flow backward. Several factors make that valve failure more likely — some you can influence, others you can't.
The core mechanism: valve failure
Leg veins push blood uphill toward the heart. When valves leak, blood pools and pressure builds, stretching the vein until it bulges. Everything below is a risk factor that accelerates this process.
Risk factors you can't change
Genetics: family history is the single strongest predictor. Age: valves wear with time. Sex: women are affected more often, partly due to hormones. Pregnancy: increased blood volume and hormones strain leg veins — more in our pregnancy guide.
Risk factors you can influence
Prolonged standing or sitting: common in nurses, teachers, and office workers. Excess weight: adds pressure to leg veins. Inactivity: the calf muscle pump helps move blood. Smoking and high blood pressure also contribute to vascular strain.
Can you lower your risk?
You can't rewrite your genetics, but staying active, maintaining a healthy weight, avoiding long stretches of standing, and wearing compression when needed all help. See our prevention guide for specifics.
Want a quick, private starting point? Take the risk assessment with our free educational tool.
Take the risk assessment →Frequently asked questions
Are varicose veins hereditary?
Yes — if both parents had them, your risk is substantially higher. Genetics influence valve and vein-wall strength.
Does crossing your legs cause varicose veins?
No, that's a myth. Sitting or standing still for long periods matters far more than leg position.
Can exercise cause varicose veins?
No — regular movement helps. High-impact strain alone doesn't cause them, and the calf-muscle pump actually improves circulation.
Medical disclaimer: This article is for general education only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with questions about a medical condition. SOLVEIN is an investigational device and is not FDA-cleared.