Final answer:
Hypercapnia is associated with an increase in muscle contraction due to the stimulation of hyperpnea, which increases the rate of breathing.
Step-by-step explanation:
Hypercapnia refers to an increase in the level of carbon dioxide (CO2) in the blood. When CO2 levels rise, it triggers an increase in the rate and depth of breathing, a process known as hyperpnea. This increased ventilation helps to eliminate the excess CO2 and maintain blood pH levels within a normal range.
So, to answer your question, hypercapnia is associated with an increase in muscle contraction because it stimulates hyperpnea, which leads to an increased rate of breathing.