Meaning of query age in pg_stat_activity

I'm using the following to detect long running queries in a webapp that is high on cpu:

SELECT pid, age(clock_timestamp(),query_start) as age, usename, query, state from pg_stat_activity order by age;

When the cpu is 100% and the app slowing down, i can see that some queries have a long age.

Running the same queries in psql is very fast, however. The db itself is low on cpu.

Is the age value as i calculate it representing the time spent by the database to execute the query or does it also include the time to read the result ? In other words, if the client is starving on cpu, will i see higher values of age ?

Regards,

Jan