Is this a run-on sentence?
On average, office workers spend more than five hours sitting at their desks, researchers believe that extended periods of sitting can have a negative impact on overall health.
A: no
B: yes
This is a run-on sentence. It is a comma splice formed from two sentences run together, joined by just a comma.
On average, office workers spend more than five hours sitting at their desks, researchers believe that extended periods of sitting can have a negative impact on overall health.
Here is one way to fix the run-on sentence:
On average, office workers spend more than five hours sitting at their desks. Researchers believe that extended periods of sitting can have a negative impact on overall health.