Pronounced veins are a normal response to exercise. It’s usually a sign of being healthy because it points [to] the fact that you’re working out. These changes are positive and symptomatic of the hard work that has been put in either by exercising or training hard for athletics. They show that our body is strong and powerful.
Whenever a muscle is being exercised, there’s an increased need for oxygen and nutrients. Because our blood transports both oxygen and nutrients, more blood flow is directed toward the muscles. Our arteries carry the oxygen-rich blood from our heart to the tissues in our body, such as the muscles we work during exercise, and the veins carry blood back to our heart “The blood flow in arteries is faster than the blood outflow in our veins, which causes a slight backup in the veins.” This causes an increase in pressure in our veins, which makes them more visible.
Strength training causes the muscles to engorge and swell with plasma. This pushes the veins closer to the surface.
Factors of vein visibility are workout type, percent body fat, amount of muscle mass, genetics, hormones, age, hydration levels.
Decreased body fat will also lead veins to appear much more prominent, since these veins are within the subcutaneous tissue
Athletes tend to be lean and have less body fat surrounded their veins, the veins in athletes tend to be more visible.
References:
https://www.healthline.com/health/fitness-exercise/lifting-veins-pop#3
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