Bad news for standing desk zealots: you may not be as superior to your seated counterparts as you think. Researchers at the University of Sydney have found that standing desks do not seem to reduce the risk of heart disease — and they may actually increase circulatory issues like varicose veins.

A new study says that using a standing desk at work promotes health, but it can be too much of a good thing. The trick is finding a balance between time spent sitting and standing.