If you are referring to veins that are difficult to cannulate for IV therapy or blood draws gently warming a limb with a warm towel helps (not hot, never in a microwave). If you are asking about overall vascular health some of the best ways to improve your vasular health are sensible eating, low fat diet, weight loss and moderate exercise. You should always consult your physician before making changes to diet or embarking on an exercise regimen.
because their is more oxygen in their blood
Veins
Veins return blood to the heart.The pulmonary veins.
Varicose veins form when blood pools in the veins.
because you blood is inside your veins.
veins are blood vessels
blood vessels that carry blood toward the heart are called veins.
Veins have valves in them which help transport the blood.
Blood flow is faster in arteries than in veins. Blood flow in veins is lower pressure.
Veins carry deoxygenated blood to the heart
Blood in veins is sent to the heart to get oxygen.
The veins return the deoxygenated blood to the heart.