Lowlander like you living at Sea level but ride the hills round here with a Max of 850ft. Few years ago I went to the Alps and initially at 3,000ft- just walking was testing the Lungs but out with the bike and rode the hills and the steepest ones in the area for a week in preparation for Ventoux. May only have been 6,000ft but without that week of aclimatisation I doubt I would have got to the first Cafe-Only 400ft above the village at the bottom.