hiiiiii obviously exercise pushes your herat to pump fast and supply blood as reuire so it leads to increase in heart rate but no need to worry it is absolutely normal anxiety and stress both have same mechanism comes under sympathetic flow from brain and this result in increase your heart rate no heart test will come positive so never go for that try to control stress by exercise meditations yoga proper sleep healthy diet hanging out with frds and open communications don t be shy enjoy music and hobbies do pleasurable activities no need to worry if any than try to understand and modified it think positively if required than take etizolam .5 mg to control tour stress and anxiety hope u will get best thank u