I've climbed Mount Kilimanjaro over 300 times and now guide others. Even fit, healthy tourists are often unprepared for how difficult the hike can be.

• Justin Stephen Mtui has climbed Mount Kilimanjaro over 300 times as a porter and guide.
• He started his tour company Climbing Kilimanjaro in 2008 to improve the treatment of porters.
• Mtui said even fit, healthy tourists are often unprepared for how difficult the hike can be.

This as-told-to story is based on a transcribed conversation with Justin Stephen Mtui, a Kilimanjaro summit guide. The following has been edited for clarity and length.