How to stay young as long as possible

In this photo Nikola Tesla was 63 years old. Who would have thought? He looked like 40. And here's what he wrote in his diary about the secret of his very young appearance. Tesla was not only a genius but he had a huge heart and this is the main reason why I decided to talk to him because he would serve as a model for us.
Tesla tells us:
"From childhood I had to take care of myself. It caused me much suffering but, to my present view, it was a blessing in disguise, because it taught me to appreciate the inestimable value of introspection in the preservation of life, and to achieve success. The demands of work and the steady stream of impressions developing in our consciousness through the door of wisdom make modern existence hazardous in many respects.

Most people are so absorbed in thoughts of the outside world that do not realize what is happening inside of them. The premature death of millions of people is mainly due to this cause. Those who have this kind of thinking, make a common mistake to avoid obvious dangers ignoring the real ones. And what is true for one person that is more or less true for everyone. The proof of this is, for example, the prohibition. In the United States the drastic measures are implemented to prevent the consumption of alcohol, but the fact is that coffee, tea, cigarettes, chewing gum and other stimulants which are freely indulged in even at the tender age are much more harmful to the nation considering the number of people who succumb. For example, during my studies I collected the necrologues published in Vienna, at home of coffee drinkers I found that the deaths caused by heart problems sometimes reached nearly 67 percent of the total. Similar observations can be made in cities where the consumption of tea is excessive. These delicious beverages excite and gradually exhaust the thin fibers of the brain. They also seriously affect the arterial circulation and should be enjoyed very rarely as their deleterious effect is slow and imperceptible.

Tobacco, on the other hand, is conductive to easy and pleasant thinking and detracts from the intensity and concentration necessary to all original and vigorous effort of the intellect. Chewing gum helps for a short period of time, but soon dries out the glands and inflicts irreparable damage, not to speak of the disgust it creates. Alcohol in small quantities is an excellent tonic, but is toxic in its action when absorbed in larger amounts, and it is quite irrelevant whether ingested as whiskey or produced in the stomach from sugar.  But it should not be overlooked that all these elements are great eliminators that help nature in upholding its stern but just law of the survival of the fittest.

The truth is that we need stimulants to work better under present living conditions, and that we must exercise moderation and control our appetites and inclinations in any way.

That is what I have been doing for many years, in this way maintaining myself young in body and mind.  Abstinence was not always to my taste but good experiences that I got are my greatest reward now. Just in the hope of converting some to my precepts and convictions I will recall one or two.
Some time ago I was returning to my hotel.  It was a very cold night, the ground was slippery, and there was no taxi.  Half a block a man was following behind me, evidently as anxious as me to get under cover.  Suddenly my legs went up in the air.  In the same instant there was a flash in my brain, the nerves responded, the muscles contracted, I swung through 180 degrees and landed on my hands.  I kept on walking as if nothing had happened when the stranger caught up with me.  "How old are you?" he asked, surveying me critically.  "Oh, about fifty-nine," I replied.  "What of it?" "Well," said he, "I have seen a cat does this but never a man." 
About a month ago I wanted to order new eyeglasses and went to an optician who examined me.  He looked at me incredulously as I read off with ease the smallest print at considerable distance.  But when I told him that I was more than sixty he gasped in astonishment.  Friends of mine often remark that my suits fit me like gloves but they do not know that all my clothes are made to measurements which were taken nearly 35 years ago and never changed.  During the same period of time my weight has not changed even a pound."

• From the book "Moji izumi" (My inventions) by Nikola Tesla published by the Museum of Nikola Tesla (Belgrade)