37Mountain lakes offer some of the best fresh water dive sites. You can find rivers with walls of granite that have been polished by centuries of flowing water. Some lakes offer amazing visibility giving the impression that you are hovering in mid-air rather than underwater. You can also expect geological features such as steep dropping stone walls. Dives at altitude may require you to have excellent thermal protection but are worth the additional effort.

At altitude the atmospheric pressure is lower than at sea-level. This reduced pressure has consequences that must be accounted for. Before enjoying the excitement of altitude diving, you must be aware of such consequences and know how to deal with them. The altitude initiation is meant for that purpose.

The obvious follow-up of altitude is that the diver returns to a lower atmospheric pressure after the dive. This reduces the tolerance for nitrogen and thus increases the risk of decompression sickness. Diver must reduce their exposure to nitrogen to account for their reduced tolerance.

In addition to nitrogen, lower oxygen levels and the reduced pressure must be taken into account.

Your instructor will want a completed medical statement from you. In some regions a medical statement with only “no” answers will be sufficient for participation in the course. In other regions a medical signed and stamped by a medical doctor will be required and must unconditionally say that you are fit for diving.

You start this course by downloading the book and reading it. Your instructor will add to the information provided in the booklet and will guide you through calculation examples. For that part you might need a dive table. Participation in the practical part of the course requires a minimum age of 10. Once the theory is done, you make one dive at altitude, which may be combined with other courses.

If you prefer to read your book on paper, then ask your instructor. The price for the paper version of this booklet is €4.90. If you cannot find a SCUBA C&P instructor in your area, then please contact us via info@scuba-courses.com.