Final answer:
Forced breathing occurs when there is a ventilatory effort but no or very little airflow. It can happen during exercise or active thought that requires muscle contraction for both inspiration and expiration.
Step-by-step explanation:
During forced breathing, the ventilatory effort persists, but airflow is either absent or nearly absent.
This can happen during exercise or when there is active thought that requires muscle contraction for both inspiration and expiration.
Forced breathing is characterized by increased breathing rate and depth to meet the increased oxygen demand of the body.