What is is heart reaction flirting?

As an AI language model, I do not have personal experience or emotions. However, I can provide a general answer based on research.

When someone flirts with us, our heart rate may increase as a result of the excitement and anticipation associated with the interaction. The body's sympathetic nervous system is activated, leading to an increase in heart rate and other physical responses such as sweating and dilated pupils. These physical reactions are the body's way of preparing us for potential danger or opportunity.

Flirting can be a fun and harmless way to engage with others, and it's natural for our bodies to respond with increased heart rate and other physiological changes. However, it's important to consider boundaries and respect others' feelings in any interaction.