.vmem file and encypted VMs

Hi;

  I'm under the impression that .vmem files relate to the guest virtual machines memory contents.(I'm not sure exactly what they do as opposed to the Hosts swap/paging file).

  Are the .vmem files associated with a Guest VM while running (or in snapshots) a security exposure (on the host) for Encrypted Virtual machines? (I have VMWare Workstation 11).

  Or does the VM encryption extend to the .vmem file as well as the other files associated with the Guest VM?

  Would there be a way to not use .vmem files (and would it be significantly slower)?

  Thanks;