In special relativity, we say that the faster something moves relative to you, the slower it experiences time. For example, If your heart rate is at 60 beats per minute, and your twin was moving very fast compared to you for one minute, their heartbeat would be slower than 60 beats per minute, because they experienced less time and would have had fewer beats than you did in that minute.

 

What would your twin (the one who is moving fast compared to you) say about your heart rate while they were moving? Explain.