Encoding features in sklearn
LabelEncoder converts strings to integers, but you have integers already. Thus, LabelEncoder will not help you anyway.

Wenn you are using your column with integers as it is, sklearn treats it as numbers. This means, for example, that distance between 1 and 2 is 1, distance between 1 and 4 is 3. Can you say the same about your activities (if you know the meaning of the integers)? What is the pairwise distances between, for example, "exercise", "work", "rest", "leasure"? 

If you think, that the pairwise distance between any pair of activities is 1, because those are just different activities, then OneHotEncoder is your choice.