There are two types of memory, declarative and procedural memory: declarative memory stores all facts and events that can be verbalised and consciously remembered and is therefore also referred to as knowledge memory. If part of it is no longer used, e.g. a foreign language learnt at a young age and then not used for a long time, it is increasingly forgotten because the existing networks become fragile. This is also due to the fact that declarative memory is located in the hippocampus and shrinks by one per cent per year from around the age of 20. Skills, habits or behaviours such as movement sequences during sport, cooking or playing music are stored in the procedural memory, which becomes so solidified after some time of practice that it can be recalled even after a long break, i.e. a woman with dementia may no longer know what a Schnitzel is, but if you start the steps of cooking with her, she can remember them again. However, the natural degradation process of the brain can be counteracted by sufficient exercise.