What causes a hollow sensation around the navel?

A hollow sensation around the navel can be caused by various factors, including gastrointestinal issues such as gas, bloating, or constipation. It may also result from muscle tension or strain in the abdominal area. In some cases, this sensation could indicate underlying conditions like hernias or infections. If the sensation is persistent or accompanied by other symptoms, it's advisable to consult a healthcare professional for proper evaluation.