It's likely a higher amplitude, that is. In radio, normally, the electricity current.
Yes, it may be related to the sound signal volume indeed.

Yet, hardware or a human, as a recipient has limits in terms of amplitude, the current, and either ears may get damaged, or brain get fried, or worse, unfortunately.

Six men are likely to have been accidentally exposed to high levels of very high frequency (VHF) radiofrequency radiation (100 MHz) while working on transmission masts; four men in one incident and two in another.

Source

Human cells die at about 107 degrees Fahrenheit or above, and when contact is made with a strong RF transmitting element the tissues near the point of contact rapidly heat well above this level. In severe cases this can cause an RF burn.

Source