00:00It could be that your hair could have traveled through time.
00:03Let me explain.
00:04They will not use a time machine and go back to the 1800s to talk to your great-grandparents.
00:10But everyone has done, or will do, the sad experience of discovering a strand of white hair
00:15by saying,
00:16I'm getting old.
00:17But listen.
00:18Scientists have good news for you.
00:21They may have found a way to reverse the process
00:24and give color to your beautiful curls,
00:26at least for a while.
00:28In a study dating from the 1970s,
00:30it was a question of a man who had three light hair at the tip and darker near the scalp.
00:35This seemed to mean that the usual process of graying hair,
00:39which begins at the root,
00:41had in its case done things the other way around.
00:44Today, a new study will bring us even more solid proof of this phenomenon.
00:49Specialists have examined the hair of several people of different ages and backgrounds.
00:54What they discovered may seem a bit surprising.
00:57It would seem that our white hair is linked to our level of stress.
01:01The way we feel psychologically could be reflected on our head.
01:05This new approach suggests that there could be a lapse of time
01:09during which our graying process could be reversed.
01:13A few years ago,
01:15an expert from the University of Columbia was wondering about the aging process.
01:20He thought that, just as some parts of our body age before others,
01:24our hair does not all turn gray at the same time.
01:27Perhaps the hair that turns white first
01:29are, in a way, the weak links of the chain.
01:32While talking to his colleague, he had a click.
01:35If he could find half-gray hair and determine its growth rate,
01:39he could know when it had started to lose its color.
01:43Luckily, his colleague found such hair on his head,
01:46and their project began.
01:48They soon found about 14 people,
01:50young and less young,
01:52with such meshes of bicolor hair.
01:55They even came up with a method
01:57to observe the tiny changes in color of their hair.
02:01The results were amazing.
02:03Some gray hair found their original color,
02:06and not only on the head, but also on the hair of the body.
02:10Today, we generally see that gray hair appears around the thirties.
02:16Well, these scientists think that this is the best time to expect a reversal.
02:21And even if your head is full of gray hair,
02:24some of them could still change.
02:27This study was considered promising by experts from different fields.
02:31They think it could show us
02:33how the changes related to the age in our body can be reversed.
02:37Of course, for now, it's just hair, but who knows?
02:41One day, perhaps, we will be able to reverse the signs of aging of our skin or muscles.
02:46This research is not limited to the color of hair.
02:49These scientists wanted to know
02:51if stress played a role in graying hair.
02:54Everyone has heard of people
02:56whose hair turns white overnight
02:59when they are confronted with traumatic events.
03:02The researchers therefore asked the participants
03:05to tell their most stressful moments over a period of one year.
03:08By associating these events with hair color changes,
03:11they found that the major moments of stress or relaxation
03:14corresponded well to changes in hair color.
03:18For example, the hair of a man
03:20had started to change color during his vacation,
03:24while a woman had gray hair,
03:26which corresponded to a very difficult period of her life.
03:30Of course, scientists from all walks of life praised these studies,
03:34but they did not fail to remind us that this project was just the beginning.
03:38Other studies must be carried out
03:40so that we can fully benefit from these results.
03:43What is the next step?
03:45Scientists now want to deepen the link
03:47between stress and gray hair.
03:49They hope to follow people over time
03:51to see how their hair and their level of stress evolve.
03:54Some think that in the future,
03:56our hair could be a window to our past experiences.
04:00Just like trees have horns that indicate their age,
04:03our hair could contain secrets about the events of our life.
04:07But stress or not,
04:08what is the process that causes graying hair?
04:11First of all, let's tackle a widespread myth.
04:14It turns out that hair does not really turn gray,
04:17it just loses its color.
04:19Once your hair has taken a certain color,
04:22whether it is brown, black, blonde or even red,
04:26it retains this shade all its life,
04:28unless you decide to give it a new color with a dye.
04:32As we age, our hair loses its memory a little and produces fewer colors.
04:37Thus, after a certain number of birthdays,
04:40when our old hair falls and new ones appear,
04:43there is more chance that it will be gray.
04:45If you wonder when you will see your first gray hair,
04:48check your family albums.
04:50Your genes, transmitted by your ancestors,
04:52generally decide the right time.
04:57Besides, why do we have more hair on the head than hair on the rest of the body?
05:02First, we must understand why most animals have fur.
05:06It turns out that, if they are a little old,
05:09it is to feel good in the heat when the temperatures drop.
05:12And also to protect themselves from the sun's rays.
05:15In this case, why did our ancestors lose most of their fur?
05:21Because they showed creativity.
05:24They found new ways to stay warm and protect themselves.
05:28By using fire, by building shelters and by dressing up.
05:32However, it is not because they could survive without fur
05:36that they lost all their hair like magic.
05:38They must have a good reason to become a beard.
05:41There are many theories on this subject.
05:44One of them suggests that it could have been too hot for us, at some point.
05:48Another indicates that some of our ancestors would have spent a lot of time in the water.
05:52The fact of having so much hair all over the body could have made them fat.
05:56Obviously, scientists have not yet found the exact reason.
06:02So, what about the hair on our heads?
06:05Why are they still there?
06:06The explanation is very simple.
06:08Humans have evolved to walk on their two feet.
06:11This means that our heads have become a bit like sunflowers,
06:14always facing the sun.
06:16However, we know that the sun can be very intense,
06:19especially in certain regions of our planet.
06:22Our hair therefore serves as an integrated cap.
06:25But that is not all.
06:26Our head, even if it is not very large compared to the rest of our body,
06:30is very busy.
06:31As it is always active, it creates heat.
06:34And our hair prevents this heat from escaping.
06:37Like an integrated natural cap.
06:39Whether it is gray or not,
06:41our hair strands could become more useful in the future.
06:44Do you wonder?
06:45Every time you go to the hairdresser,
06:47where are all these hair?
06:49For now, they are thrown away.
06:51Fortunately, the ingenious minds of Queensland had an incredible idea.
06:55Instead of considering hair as waste,
06:58they saw a potential energy source.
07:00They burned the hair delicately and extracted carbon from it,
07:04which they transformed into tiny grains,
07:06like the dust of the magic utensil.
07:08Because it really was magic.
07:10They sprinkled solar panels with this powder.
07:13And the panels started to work better and to be more stable.
07:19Your hair also contains a pigment called melanin.
07:23I spare you the complicated details,
07:25but this chemical substance is sensitive to light.
07:29Discovering this phenomenon,
07:31a Nepali teenager said to himself,
07:33why not use hair instead of expensive silicon in solar panels?
07:38Imagine that you did exactly that.
07:41You would give a large number of people
07:44the possibility of using energy in a less expensive way.
07:48This could well be the next important step
07:51to make solar energy more accessible and more affordable.
07:54Then, imagine this.
07:56You are grinding a delicious salad for lunch.
07:59Did you ever think that hair could help grow lettuce?
08:03Thanks to scientists from the University of Singapore,
08:06this could soon become a reality.
08:08They have developed a way to grow plants,
08:11especially in cities,
08:13using a method called hydroponics.
08:15No more need for soil.
08:18Instead, they use a special mixture based on hair.
08:22Let's go over the process.
08:24Researchers collected hair in places such as hair salons,
08:28and extracted a substance called keratin.
08:31They then mixed this keratin with cellulose fibers,
08:35which made it more resistant.
08:37Once dried, this mixture turns into a paste,
08:41perfect for growing plants.
08:44They chose to experiment
08:46with microgreens and delicious vegetables,
08:49such as chuchine and roquette.
08:51Well, that's enough.
08:53I'm going to make a little salad.
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