Physically Demanding Work – Alberta

Hi,
We are located in Ontario and we have an employee that suffers from high blood pressure and takes medication. He is required to perform physically demanding work. Can we require him to provide medical proof that he is capable of performing his responsibilities? Can this be an ongoing requirement (eg. needs to confirm every 3 months that he is physically capable)? He has missed time at work due to medical reasons.
Would this type of condition be protected under Human Rights legislation? “It is the OHRC’s position that anticipated disabilities are also covered by the Code.[19] This would apply where a person does not currently have a disability, but they are treated adversely because of a perception that they will eventually develop a disability, become a burden, pose a risk, and/or require accommodation”
Thanks