Veins bulging from your body often look large, rigid and under high pressure. Many people assume this is the circulatory system's response to heightened demands resulting from exercise. Although exercise does have effects in the body that can change the appearance of your veins and arteries, it is not a matter of new ones appearing, or old ones enduring more stress. In fact, the appearance of veins under your skin when weightlifting has very little to do with the veins at all.
Effects of Exercise
Any type of exercise elevates the heart rate to some degree. This is a physiological response to an increased need for oxygen in the body, particularly in locations where work is being performed. The heart rate and breathing rate increase to compensate for the increased work, which is fueled through blood flow to exercised locations, such as the muscles.
Role of Plasma
The changes in the appearance of your veins actually has little to do with what occurs in the veins themselves, according to "Scientific American." In fact, these effects in your veins are the product of changes in the muscle matter surrounding them. The body's plasma flows into muscles during exercise and causes them to swell and harden. The hardening of muscle pushes inset venous tissue to the surface of the muscles and against the skin, making it more visible, while the function of the veins remains largely unchanged.
Volume and Pressure Myth
The long-held belief of the cause of bulging veins was that exercise forced the heart and circulatory system to distribute blood faster, leading to an increase of volume and pressure in the veins that pushed out venous walls and made them more rigid. But more recent study of bulging veins has shown that pressure actually declines during exercise because circulation is improved throughout the body, distributing blood and putting less pressure on any one passageway. Volume also remains constant throughout the body and can increase in smaller capillaries while decreasing in larger vessels.
Although bulging veins are a common by-product of exercise, you can also develop more prominent veins through potential hazardous health concerns. Heart disease can contribute to bulging veins and be a precursor to a heart attack, according to "Running Times." Smoking also accentuates veins on the surface of the skin, as does excessive stress. Older individuals are more likely to develop bulging veins for this reason. If you are unsure about the cause of your bulging veins, call or visit a doctor.