What factor does NOT lead to decreased respiration?

Exercise is known to increase respiration rather than decrease it. During physical activity, the body's demand for oxygen rises, and to meet this demand, the respiratory rate increases. This response helps to enhance the intake of oxygen and the expulsion of carbon dioxide, thus facilitating more efficient gas exchange in the lungs.

In contrast, sleep generally leads to decreased respiration rates because the body's metabolic demand is lower during rest, leading to a more relaxed state. Pain can also lead to altered breathing patterns, often resulting in more shallow and rapid breathing as the body responds to discomfort. Pulmonary insufficiency complicates this further, as it impacts the lungs’ ability to ventilate effectively, which can lead to decreased oxygenation and often compensatory mechanisms that might retain lower respiratory rates under certain conditions.

Therefore, exercise is the factor that primarily stimulates increased respiration, making it the answer to the question regarding what does NOT lead to decreased respiration.