Conditional statements with more than 1 word in the same variable

I am trying to create a variable based in various business rules from another variable. Please see example below. When I am dealing with only one word I need to use as a condition I use the following code:

  physical = ['light','sedentary','medium','heavy']

  def matcher(x):
      for i in physical:
          if i.lower() in x.lower():
             return i
     else:
     return 'other'

My issue is when that are multiple words that match in a sentence, in this specific cases I wan to call 'mix'.

  Physical Demand                                          Result
    Light to medium with occasional heavy  levels           mix                        
    Light                                                   light
    Medium                                                  medium

tks.