Theory 40/Fever cycle/Onset phase
Onset Is a Set-Point Shift
The claim
Fever begins when the rate of pyrogen-driven set-point change exceeds the rate of heat gain, so the patient feels cold before the temperature rises.
01Mechanism
The hypothalamus raises its target; body temperature lags until heat is generated.
02Prediction
Shivering should precede the temperature rise.
03Refutation
Fever beginning with temperature rise would remove the set point.