We consider it to be moderade. On a scale of 1–5 (with 5 being maximum difficulty), it’s level 2. The hiking path only has a limited slope (it is not an uphill walk), but can be hilly and uneven. We highly recommend that you wear good hiking boots and warm clothes. Just remember, a guide will be with you during the walk, leading you via the easiest route over the field.
If you have any doubts regarding the hike, you should look into the option of going to the volcano via helicopter.