An anechoic chamber is designed to absorb sound waves, effectively creating a space where there is no echo or reverberation. The purpose of such a chamber is to isolate and measure the properties of sound sources without any interference from the environment.

When you are inside an anechoic chamber, you will experience a significant reduction in background noise. However, whether or not you can hear your heartbeat depends on several factors:

1. Sensitivity of Your Hearing: Some people may be able to hear their heartbeat under very quiet conditions, especially if they have good hearing sensitivity.
   
2. Design of the Chamber: An anechoic chamber is designed to absorb external sound, but it does not necessarily block all internal sounds. If the chamber is well-insulated from external noise, it may enhance your ability to hear internal bodily functions.

3. Your State of Relaxation: When you are relaxed, your heartbeat tends to be quieter. If you are anxious or excited, your heartbeat may be more audible.

4. Other Factors: Your heartbeat may be more audible if you have a medical condition that causes an unusually loud heartbeat (such as anemia or thyroid issues).

In summary, while an anechoic chamber can significantly reduce external noise, whether or not you can hear your heartbeat depends on individual factors and the specific design of the chamber. It is possible that in the extreme quiet of an anechoic chamber, you might become more aware of your heartbeat, but this is not guaranteed for everyone.