You consider life easy or hard?

hard. if it was easy i would be very rich.

Either from your natural reflexes because when your muscles lose oxygen, your muscles will relax which can force you to breathe. If in some case, your able to still hold in your breathe, The CO2 in your blood will cause the pH of your blood to fall causing you to faint. It's a natural reaction to prevent idiots from killing themselves by doing this.

˙˙˙¡ɯɐds ou˙˙˙(¡ʇı ɹǝʍsuɐ oʇ ʇsǝq ʎɯ/pɹɐɥ ʎɹʇ llıʍ ı puɐ ʇı ʞsɐ noʎ) ˙˙˙llɐ ʇɐ ƃuıɥʇʎuɐ 'ƃuıɥʇʎuɐ ǝɯ ʞsɐ 'ǝsɐǝld