Looking for values of the average human body density on the Internet, one often finds the values of 0.98 for male, 0.87 for female. Other values are 0.985 for male and female. However, I can find no scientific reference confirming these values.
Instead, I found multiple articles giving numbers closer to 1.05 for male and 1.03 for female (Durnin and Womersley, 1974). The difference probably comes from the air comprised within the lungs, but I do not know how much it can change the density and how full our lungs are in average. Would anyone have a reliable reference on this matter?
Ultimately, I would like to understand the effect of breathing on the floating in water and compare this effect for male and female. I would like to see if it can account for women tending to float, even after deep expiration. It upsets a friend in her diving lessons. :)