When the alarm is raised
This database is spending too much time waiting for bottlenecks such as locks and latches. Note that this alarm uses a score averaged over 30 minutes to smooth out any rapid movement.
For more information on your database's performance health see the SQL Server | Performance Health Drilldown.
A performance-health rating of 80% or more is considered healthy. For more information, see SQL Server | Home Page | Performance Health Panel.