This plan contains a mixture of shorter and longer sets during the training. These create environment of both high and medium heart rate, both of which have significant impact on your overall health. Training is backed up by scientific research, as well as long term experience in training individuals.
IMPORTANT: Please note that this program contains training plans which are adjusted to beginners who want to swim in order to improve their health, cardiovascular capabilities and have a solid plan to motivate them and create consistency. However, this plan WILL NOT teach you how to swim if you don't know how to swim at the moment. Never start swimming based on any plan, instructions video or friends advice if you never did it before.
If you can swim at least pool length on your own, feel free to use this plan as it is well developed, easy to follow, and created by people with years of experience. It will help you slowly increase your swimming lengths and will make your training a well organised and enjoyable experience.