Normally, the area around the eyes is well vascularized, meaning there is plenty of circulation supplied via plenty of healthy capillaries to prevent any build up of metabolic wastes and deoxygenated blood which present as dark circles.
If you don't get enough excercise, intake too much coffee, tea or alcohol or don't drink enough water, vascularization in this delicate area is reduced and the likelihood of dark circles will be greatly increased.
Left untreated over time, the capillaries are damaged and will cease to function well. Micro-circulation is reduced and the tonicity of capillaries must be repaired.
Dark Circle Prevention
Plenty of fresh water, minimal coffee, tea and alcohol and regular exercise combined with Eye Gel and Eye Cream.
The degree to which you should exercise prevention should be dictated by your hereditary tendency toward dark circles: act as soon as they appear or use a preventative treatment 2-3 times a year if you know dark circles run in your family.
Puffy upper and lower eyelids can also be attributed to lifestyle and hereditary.