Great quote from famous health advocate and runner Are Waerland

"...Running acts as a bath in pure oxygen. It opens all the pores of our skin,
ventilates our clothes, stimulates our nerves, brings our capillary muscles into action,
oxygenates our blood, burns up all rubbish in our tissues and leaves us with a good
supply of oxygen in stock for further demands. This extra store of oxygen in the
human system manifests itself physically in a feeling of buoyancy and of almost
boundless energy. Worries disappear like a mist before the morning sun in June.
Difficulties seem to exist only to be overcome. Activity is our joy. Life is glorious ...
whilst oxygen-hunger makes us languid and lazy, we gasp for air and are mentally
irritable, taking a gloomy view of everything!..."

and another one

"What is old age but a gradual, involuntary and voluntary slowing down of all our
bodily activities. If you always walk gently, slowly, respectably, step by step, you will
be an old man at 30. But if you run at 60 and 70 and 80, at least once daily for 10 or
15 minutes, you will never know old age. You will keep young until the very last
moment of your life, and you will smile at death which should come to you then, not
as the result of a devastating pulmonary fire or pneumonia, but in the form Nature
meant it to come, the heart suddenly going to rest with its last beat like a clock when
the spring has run down. When the heart stops, everything on all the canals in the vast
lagoon-city of our body also comes suddenly to a standstill. Every boatman ships his
oars, every vessel hauls down its flag. The great Silence has fallen over the whole
community. The time has arrived for breaking up, for saying 'good bye' and starting
on a new adventure."