Visible veins on your hands, arms, or legs are usually considered harmless. They can simply be a sign of aging, low body fat, or an active lifestyle. For many people, this is completely normal. However, when veins suddenly become more prominent, it may indicate an underlying health condition that shouldn’t be ignored. Understanding what causes these changes can help you take action early and prevent serious complications. Here are five potential reasons why your veins might suddenly appear more noticeable.

1. Chronic Venous Insufficiency (CVI)
Chronic venous insufficiency occurs when the valves in your veins weaken or stop functioning properly. Normally, these valves ensure that blood flows toward your heart. When they fail, blood can pool in the limbs—especially the legs—causing veins to enlarge and bulge.

Common symptoms include:

Rope-like, visible veins under the skin

Swelling, heaviness, or aching in the legs

Discoloration or even ulcers near the ankles