The database is spending too much time waiting for bottlenecks such as locks and latches.
If a database devotes most of its time to CPU and I/O and has a low single-block read latency, it will obtain a performance-health rating of 80% or more, which is considered healthy.
For more information on your database’s performance health see the SQL Server | Performance Health drilldown.
Tip: This alarm uses a score averaged over 30 minutes to smooth out any rapid movement.