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Is The Runner’s High Real? Here’s What The Science Says

Runner’s High
(Image credit: Unknown)

There is no shortage of evidence to support the idea that running is good for your mental health, and any regular runner will testify to the fact that you often feel pretty great at the end of a run, if only because you get to stop running.

It’s important to separate those things from the runner’s high, however, because those who say they experience this phenomenon describe feelings of euphoria.

Not every runner gets to experience it, though, and that includes Mariska van Sprundel. As well as being a runner, Van Sprundel is a science journalist and the author of new book Running Smart: How Science Can Improve Your Endurance And Performance (opens in new tab) (MIT Press, available 14th September), which looks at the latest sports science and how these developments can help your running.

Running Smart covers the research into the runner’s high and what could possibly cause it, so we spoke to Van Sprundel to learn more.

What is the runner’s high?

It’s described as a feeling of euphoria, combined with feeling less pain and less anxiety.

But also, it’s kind of fake because not every runner experiences it, and when they do, it’s different for all of them. Some people feel less stressed. Other people have a feeling that they can go on forever, because they’re in such a flow. Or they feel like they have lots of energy when they come home after their run. It’s difficult to pinpoint.

What is actually happening in your brain and body?

The jury’s still out on that question. There are two theories. The most popular theory is the endorphin hypothesis, which came up in the 1980s when researchers saw that after a long run, there’s an activation of endorphins in your blood. Endorphins are your body’s own painkiller, so they have some of the same properties as morphine and heroin. You have an opioid system in your brain, and when it gets triggered you feel less pain and get a feeling of happiness. Endorphins are your own morphine in that sense. It became clear that endorphins were elevated after a run, so that’s where the hypothesis came from.

Then there was a little problem because they were only measured in the blood, and it became clear that it’s such a large molecule that it can’t enter your brain because of the blood-brain barrier. This prevents viruses and bacteria from crossing from the bloodstream into the brain.

There are three types of endorphins. One is only released in the peripheral nervous system, so they don’t enter the brain and spinal cord, but can help prevent muscles from feeling pain when they are in the blood. That’s a very important function of endorphins. And then the question is if the endorphins that are in your blood can also contribute to the euphoric feeling in your brain – can they alter your mood? And that’s still a bit controversial.

The other theory is more recent – it was in 2015 this one came up. It is about anandamide. It’s kind of your body’s own cannabis. It’s a chemical with pain-relieving properties and also a rewarding molecule that can make you feel happy. This is a smaller molecule and it can enter your brain.

There was an experiment with mice to start off with. They let these mice run for five hours on a wheel – that seems like a lot, but actually for a mouse it’s not that much, so it’s not animal cruelty! They showed less fear and also less pain, and they measured elevated anandamide in their blood, and it could cross the blood brain barrier.

Do most runners experience the high at some point?

It’s a well-known phenomenon and everybody talks about it, but when you look at surveys, it’s actually pretty rare. There are a lot of athletes and runners who haven’t experienced it. I’m one of them. A lot of runners feel tired or even a little bit nauseous after a long run. It’s not that the majority of runners feel blissful.

I think there’s no doubt that running makes you feel good. That is the case for the majority of runners, but when are you just feeling good, and when are you experiencing a runner’s high? I think it’s difficult to separate the two.

Can you get the runner’s high from other sports?

Yes, runner’s high is kind of a misleading name, because you also can get the high from other endurance sports like cycling and rowing. It has been reported in both sports. It seems that duration is key to get the high – some evidence indicates you have to do one hour or more of aerobic exercise.

The experiments that have been done are only really done with moderate aerobic exercise. But there’s also one study that looked into high-intensity interval training, and that also seemed to provoke some sort of high.

Nick Harris-Fry is a journalist who has been covering health and fitness since 2015. Nick is an avid runner, covering 70-110km a week, which gives him ample opportunity to test a wide range of running shoes and running gear. He is also the chief tester for fitness trackers and running watches, treadmills and exercise bikes, and workout headphones.