There are depths in man that go the length of lowest Hell, as there are heights that reach highest Heaven – for are not both Heaven and Hell made out of him, made by him, everlasting Miracle and Mystery as he is?
Humans are amphibians – half spirit and half animal.
As spirits they belong to the eternal world, but as animals they inhabit time.
This means that while their spirit can be directed to an eternal object, their bodies, passions, and imaginations are in continual change, for to be in time means to change.
Their nearest approach to constancy, therefore, is undulation – the repeated return to a level from which they repeatedly fall back, a series of troughs & peaks.
If you watch carefully, you will see this undulation in every department of his life – his interest in his work, his affection for his friends, his physical appetites, all go up & down.
As long as he lives on earth periods of emotional and bodily richness and liveliness will alternate with periods of numbness & poverty.
Fun is closely related to Joy – a sort of emotional froth arising from the play instinct; it promotes charity, courage, contentment, and many other evils.
A thousand years from now human beings would probably continue to die of cancer and earthquake and such clownish mishaps as slipping in bathtubs.
Mankind would continue to be burdened with eyes that grow weak, feet that grow tired, noses that itch, intestines vulnerable to bacilli, and generative organs that are nervous until the age of virtue & senility.
Most people would continue, at least for a few hundred years, to sit in chairs, eat from dishes upon tables, read books — no matter how many cunning phonographic substitutes might be invented, wear shoes or sandals, sleep in beds, write with some sort of pens, and in general spend twenty or twenty-two hours a day much as they had spent them in 1930.
Tornadoes, floods, droughts, lightning, and mosquitoes would remain, along with the homicidal tendency known in the best of citizens when their sweethearts go dancing off with other men.
And, most fatally & abysmally, men of superior cunning, of slyer foxiness, whether they might be called Comrades, Brethren, Commissars, Kings, Patriots, Little Brothers of the Poor, or any other rosy name, would continue to have more influence than slower-witted men, however worthy.
Heart muscle cells have the most mitochondria, thousands per cell.
High-intensity interval training in aerobic exercises such as biking and walking cause cells to make more proteins for their energy-producing mitochondria, effectively stopping aging at the cellular level.
What would happen if all the mitochondria in your body released all their energy at once?