Here is a full translation of the main content from the article “When should you worry about veins that appear suddenly?” 1 :
Many people suddenly notice veins on their arms, legs, and even chests that they haven’t seen before. For most people, these veins are harmless and are a result of aging, genetics, or temporary changes in the body’s condition. In some cases, however, newly appearing veins can be a sign of a health problem that shouldn’t be ignored.
What causes the sudden appearance of visible veins?
There are several main reasons why veins can become more visible:
Low body fat percentage: When subcutaneous fat decreases, especially on the limbs or body, veins become more visible as the layer that covers them thins.
Exercise and weight lifting: During exercise, blood flow increases, causing veins to swell and bulge. With regular exercise, muscles grow and push veins closer to the surface.
Hot weather: Heat causes veins to dilate to cool the body, making them more noticeable, especially in the hands and feet.
Aging: As you age, the skin loses elasticity and thins, allowing veins to become more visible.
Hormonal changes: Pregnancy, menopause, or hormone therapy can affect blood vessels and circulation, sometimes causing veins to appear in new places.