Which of the following is a common physiological symptom of stress?

Muscle tension is a common physiological symptom of stress due to the body's natural response to perceived threats or challenges. When a person experiences stress, the body enters a fight-or-flight mode, releasing stress hormones such as adrenaline and cortisol. These hormones prepare the body to respond to the stressor by increasing heart rate and blood flow to muscles, which often leads to muscle tension. This tension can occur anywhere in the body, especially in areas such as the neck, shoulders, and back, and is a reflection of the body's heightened state of alertness.

In contrast, decreased heart rate typically signifies a state of relaxation rather than stress. Improved digestion is associated with a relaxed state; during stress, the body directs energy away from digestive processes. Increased relaxation also typically occurs when the body is not under stress, as stress tends to induce physiological responses opposite to relaxation. Thus, muscle tension is the most accurate representation of a physiological effect that arises from stress.