Android蓝牙VS蓝牙低能耗

I am trying to create an application that needs to exchange small size of data - just to notify that the devices are close enough - for as long as the smart phone is running. It is my understanding that the traditional bluetooth consumes significant amount of battery so that having it turned on for hours is not viable. I am looking at BLE but still concerned with the battery capacity.I am trying to create an application that needs