Another natural factor at play is aging. Over the years, skin loses collagen, a protein essential for its firmness and elasticity. As it thins and loses elasticity, internal structures like veins become more visible, especially on the hands, where the skin is naturally delicate.
High temperatures can also be a factor. In hot weather, the body tries to regulate its temperature by dilating blood vessels, which allows heat to escape more easily through the skin. This can make veins more visible after a hot bath in the summer or after prolonged sun exposure.
