Everything goes numb in that moment. Their mind empties. Their breathing, footsteps and heartbeats harmonize and block out all other sounds. Their eyes remain locked on the finish line ahead.

“It’s that second wind that you get after you’ve been running for a while,” junior women’s cross country team co-captain Katherine Gustafson said.

“You’ve hit your first wall, the pain is there and you feel like you can’t go anymore but all of a sudden, a rush will hit you and you’ll feel able to keep moving. It’s almost like hitting a restart button.”

This feeling is familiar among runners and is commonly known as a “runner’s high.”

“[What typically happens is] you go through an extreme doom and gloom [during the race] where your body will tell you that you’re tired and that you’re feeling really worn down, but then you will get to the point where your body begins to feel numb and you will enter a state of blankness,” cross country head coach and health teacher Todd Weber said.

“My recollection of it was that after you finish, you get a sense of calmness and a sense of euphoria about five minutes after the race. That sense of euphoria or calmness typically stayed with me for at least several hours.”

This sense of euphoria, this second wind, this restart is the “runner’s high.” The theory of the runner’s high has been around for at least thirty years. It has often been a topic of discussion among scientists of whether the runner’s high scientifically exists or not.

Scientists have been able to narrow the cause of the runner’s high down to a chemical that they believe is mainly responsible: endocannabinoids, small molecules that are able to pass through the blood-brain barrier and produce a “high”.

It has been found that, in recent years, exercise raises the levels of endocannabinoids in the bloodstreams of people and animals, making these molecules good candidates to underlie the runner’s high.

To test it, researchers with the Central Institute of Mental Health at the University of Heidelberg medical school in Mannheim, Germany did a test using rats on a running wheel and recorded data about their mental activity and the amount of endocannabinoids in their system.

The scientists noted elevated levels of endocannabinoids in the animals’ bloodstreams after running and that the animals seemed to be more “tranquil” after running, spending longer periods of time in lighted areas within their cages.

Even with the chemical cause clear, there are still many other factors not yet known about the runner’s high.

“I think there are a lot of factors that are involved and I think it’s a mystery as to what it exactly is. It depends on the race you’re in and the person that’s running. From my research, [what is concrete] is that different athletes experience [runner’s high] at different times,” Weber said.

For example, Gustafson said that she typically experiences it at the hardest junction of the race – the third kilometer of a five kilometer race. Meanwhile, senior women’s cross country co-captain Ella Schroth said that her runner’s high experiences varies substantially.

“Sometimes I won’t get [a high]. Other times, I get it just that race and the high makes you want to keep running. It always puts me in a good place,” Schroth said.

Schroth’s words echo many past runners, one of them being former long distance ultramarathon runner Yiannis Kouros, a man who many have called the “Running God.”

In an article Kouros published in UltraRunning magazine in March of 1990 called “A War Is Going On Between My Body and My Mind,” he recounts his experience with runner’s high.

“During the ultras I come to a point where my body is almost dead. My mind has to take leadership. When it is very hard, there is a war going on between the body and the mind. If my body wins, I will have to give up; if my mind wins, I will continue,” he wrote.

When his “mind wins”, Kouros said he feels like he stays outside of his body.

“It is as if I see my body in front of me; my mind commands and my body follows. This is a very special feeling, which I like very much. . . It is a very beautiful feeling and the only time I experience my personality separate from my body, as two different things,” Kouros said.

Whether you want to look at the runner’s high scientifically as the rise of endocannabinoids flowing into your brain, or more as the mental feeling of invincibility, it is a very real thing to a number of different runners.

“You just need to experience it in order to understand it. It’s just something else,” Schroth said.