How to get a fast heart beat besides exercising and drinking caffeine ?

So many ways!: Fever, anemia, pain, anxiety, panic/fright, asthma inhalers, amphetamines, cocaine, hemorrhage, excess thyroid hormone, infection, epinephrine, dehydration, congestive heart failure, carbon monoxide poisoning - there are many more: i can't think of them all!

Stressing out.: Thinking about things can raise hr - or lower. Pain, fear. Many stimulants and meds can raise heart rate. Peripheral vasodilation as in heat exposure. Low inhaled oxygen content. A good burn or a good anemia. A pulmonary embolism or dehydration or heart attack. None of these are as good as exercise and coffee.