According to Wikipedia, zest for life is how you subjectively feel about the joy in your own life. And indeed, what is more enjoyable than meeting friends, drinking a glass of wine, undertaking something or just cooking and having a good time together?
By increasing the oxygen supply, you become more powerful. As the sun is important for the growth of plants, so the oxygen motor is for all intra cellular physical processes. With more oxygen, everything is simply better, lighter, more effective – inside as well as out. Error ratio is lower and defeat less important. Only through active metabolism is oxygen taken to the cells in the body. And only this way is it possible to become physiologically younger.
By swinging daily on the trampoline, one copes better with the demands of daily life. Life makes more sense, your perspective seems right, the future is exciting. This way there is no need to fear growing old.
Conclusion:
By deciding to live an active, bouncing life from now on, it is possible (despite a prognosis to the contrary) to stay healthy and retain the ability to remain individually active whilst feeling secure. All this combined leads to an increased zest for life.