Caffeine is a stimulant with a quick onset and long lasting effects. It can elevate blood pressure, increase the heart rate, it is a mild diuretic with some fluid loss, and may make it difficult to sleep easily. It also has benefits including as a stimulant with improve alertness and mental concentration. There is not any clear effect on the veins and the choice of how much caffeine is beneficial depends on how well it is tolerated and your total daily dose. If you have trouble with elevated blood pressure, an irregular heart beat or insomnia then you should avoid caffeine, but it should not effect your veins.
The caffeine has no effect on varicose veins. Caffeine increased the blood pressure in the arteries and should not effect your venous circulation. Your varicose veins are hereditary and can be the consequence of trauma and hormones.
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