Most people will pass out with just 4 or 5 G forces. Hearts will not be able to pass blood to the entire body under such pressure. The brain will not receive enough oxygen which can cause loss of consciousness.
Below is a calculation expressing how much force is required to knockout uke who has a height of 183 cm and a weight of 173.5 pound during kake.
radius=183.388 cm* 42%
=77.02 cm
rub=46.54cm
Iu1=15.8 kgm2
atan = 5g*9.8m/s2
5g*9.8m/s2= 77.02 cm* (46.54cm*F)/15.8kgm2
F=2139N
From that calculation, uke could be knocked out if tori can provide 2139 N of force during the execution. The same amount of force would be required to lift a 480 pound(217 kg) object. This number might vary depending on the weight or height of uke. The calculation process is shown below.
Formula: F=(5g*9.8m/s2*Iu1)/rub
rub=Length from center of mass to shoulder.
Iu1: the moment of inertia for a human standing with one arm extended. (go back to tsukuri to see how to calculate it)