Final answer:
Increased heart rate is a physical symptom of stress, which is part of the body's 'fight or flight' response to perceived threats or challenges.
Step-by-step explanation:
Among the choices provided, increased heart rate is a physical symptom of stress. When under stress, your body reacts with a series of physiological changes to prepare you for action. This response, often referred to as the 'fight or flight' response, includes an accelerated heart rate, quicker breathing, and muscle tension. These changes are initiated by the nervous system and are meant to enhance your ability to face a perceived threat or challenge.
While short-term stress can stimulate and excite, leading to improved concentration and performance in activities like musical performances and athletic competitions, long-term stress can have negative health implications. Maintaining elevated heart rates over extended periods is not healthy, and consistent, long-term stress can contribute to a variety of physical illnesses, including cardiovascular problems.