The worker must:

•    be at least 18 years old (vergl. Art. 4 / ArG V5 & SR 822.115.2)
•    be physically and mentally fit (Selbstdeklaration)
•    not have problems with drugs or alcohol
•    not be scared of heights

Currently workers are not required to pass a physical exam before performing dangerous work at height.
Nor are they examined for their suitability for the job (similar to BG41 in Germany).
The worker is however required to disclose any health problems to the employer whenever the health of a third person may be put at risk.

At risk training sessions for working at height, it is recommended that the participants fill out and sign a declaration of their current health condition.

Here is one example.