In the last two weeks I was hiking around my small city (Višnjan). I made a total of 737.96564616 meters uphill, 32575.07452042m long (32680.59386254m if counting elevation).
How do I know those numbers?
Because there is a new option in TrackProfiler -- You can export track statistics in a CSV file. For all files or for files with specific tags. All I did was to export in CSV files with tags "visnjan" and "hiking" and then computing the sum of columns with Excel.
If you tag all your hiking tracks with "hiking", tracks when you were in Italia with "italy" and Alps tracks with "alps" -- just enter "hiking italy alps" in the new CSV exporter form. The resulting file will contain data for all those tracks.