Please use the Question Tags to state the named and full version number of the Story Format you are using, as answers can vary based on this information. I will assume you are using Harlower v3.0.2 as that is the current default story format.
You could use a story variable to record what the maximum health or stamina is, and then use that variable when reseting the associated health or stamina.
(set: $healthMax to 10)
(set: $health to $healthMax)
(set: $staminaMax to 10)
(set: $stamina to $staminaMax)