Since it indicates this is "as if you were concentrating on a spell", the rules for concentrating on a spell apply.
From p. 203 in the Player's Handbook:
Normal activity, such as moving and attacking, doesn’t interfere with concentration.
Things that may interrupt your concentration are:
Casting another spell that requires concentration.
Taking damage. Whenever you take damage while you are concentrating on a spell, you must make a Constitution saving throw to maintain your concentration. The DC equals 10 or half the damage you take, whichever number is higher. If you take damage from multiple sources, such as an arrow and a dragon’s breath, you make a separate saving throw for each source of damage.
Being incapacitated or killed. You lose concentration on a spell if you are Incapacitated or if you die.
Also, the DM may determine that certain "environmental phenomena" may break your concentration. The player's handbook provides, as an example, a wave crashing over you on a storm tossed ship.