Which factor can increase heart rate?

Increased physical activity is a well-documented factor that raises heart rate. When the body engages in physical activity, there is a heightened demand for oxygen and nutrients by the muscles. To meet this demand, the heart pumps more frequently and forcefully, resulting in an elevated heart rate. This physiological response is driven by the autonomic nervous system, specifically the sympathetic branch, which stimulates the heart to accelerate its rate to ensure adequate blood supply during exercise.

Other factors, while they may influence heart rate in different contexts, do not directly cause an increase in heart rate as consistently or predictably as physical activity does. Increased oxygen levels may signal the body that less effort is required, possibly reducing heart rate. Dehydration often leads to the body conserving water, which can create cardiovascular strain and potentially affect heart rate variably depending on severity. Relaxation and meditation typically lower heart rate by activating the parasympathetic nervous system, promoting a state of calm. Thus, physical activity is the dominant factor that consistently and significantly increases heart rate during exercise or high-intensity activities.