Hi francisloe,
these are some tips that people in my country use to do before they step in medical check.
_ Go to bed early do not work at night.
_ Drink coconut water as much as you can.
_ If you are smoker or drinker, try stop smoking or drinking in advance as long as possible.
You will be banned to migration to Canada if you have HIV only however, if you have any decease like syphilis, tuberculosis.. you have to receive medical treatment before you migrate to Canada. The treatment time some time take very long 2 or 3 years or even longer.
good luck my friend,