ANSWER:
Caffeine is a stimulant that makes your heart rest increase, and stress increase. The reasoning for this phenomenon is caffeine stimulates your fight or flight instinct, so if you have anxiety or stress it will worsen it. Studies have shown that drinking caffeine can cause anxiety attack or make you jittery. Caffeine can facilitate the release of natural hormones that act on the heart, this hormone is similar to adrenaline causing your blood pressure to increase immensely.