I do this too. I really enjoy gardening but I usually pay for a day out. I don't always get dizzy as much because I have an anti-syphon device just below my shunt which regulates the flow of fluid. But I'm wondering if the the ETV (not sure if that is right) is enough to regulate your hydro. But after a day of gardening if I have been bending over alot. I will have a really bad headache for the next 24 hours. It will even feel bruised feeling.