* Variability! see my post in the forums (variability in variable you want to change is defined by the fact that it changes sufficiently for you, but what if the intervention only comes after deciding on variable) and that is only the target variables like HRV | * Variability! see my post in the forums (variability in variable you want to change is defined by the fact that it changes sufficiently for you, but what if the intervention only comes after deciding on variable) and that is only the target variables like HRV |