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The Runner's High Explained: What It Is And Why It Happens
Most runners have heard of the runner's high, but not everyone has experienced it. Some describe an unexpected feeling of euphoria during a run, while others experience a sense of calm, happiness or mental clarity that continues after they have stopped. For a short period, running can feel particularly enjoyable, even when the body is working hard.
Scientists have spent decades investigating what causes this sensation and why some people experience it while others do not. Once widely attributed to endorphins, the runner's high is now thought to involve another group of naturally occurring chemicals called endocannabinoids. But what does the research actually tell us, and can runners do anything to increase their chances of experiencing it?
What Is The Runner's High?
The runner's high describes a temporary feeling of euphoria or enhanced wellbeing that some people experience during or after running. It can involve feelings of happiness, relaxation and reduced anxiety, sometimes accompanied by a sense that the physical effort of running has become easier to manage.
The experience varies considerably between individuals. Some runners describe a noticeable change in mood, while others simply feel unusually relaxed or find that their everyday worries become less distracting. It may develop gradually rather than arriving as a sudden burst of happiness.
There is no universally accepted definition or reliable test for the runner's high. This makes it difficult to establish how frequently it occurs or why some runners experience it more often than others.
Is The Runner's High Real?
Yes. Research has demonstrated that running can produce measurable improvements in mood, including increased feelings of euphoria and reduced anxiety. However, the biological processes responsible are more complicated than scientists originally believed.
For many years, the runner's high was attributed to endorphins, naturally occurring chemicals that help regulate pain and the body's response to physical stress. Because endorphin levels can increase during exercise, researchers considered them a possible explanation for the positive feelings associated with running.
However, endorphins circulating in the bloodstream do not readily cross the blood brain barrier. This means that increased blood levels cannot, on their own, explain changes in mood.
An important human study published in 2021 investigated this question by blocking opioid receptors in participants who completed 45 minutes of moderate intensity running. Researchers found that the runners still experienced increased euphoria and reduced anxiety, suggesting that these effects did not depend on opioid signalling.
The findings strengthened interest in another possible explanation: the body's endocannabinoid system.
What Are Endocannabinoids?
Endocannabinoids are naturally occurring signalling molecules produced by the body. They form part of a system involved in regulating mood, stress responses, pain and several other functions.
One of the best studied is anandamide, which can cross the blood brain barrier and influence processes associated with emotional wellbeing. Its name is derived from a Sanskrit word associated with bliss, reflecting its connection with feelings of pleasure and happiness.
Research has shown that aerobic exercise can increase circulating levels of anandamide. A systematic review and meta-analysis published in 2022 found that exercise was consistently associated with increases in this chemical, although the size of the response varied considerably between studies.
Another study published in 2024 examined changes in mood and endocannabinoid levels following a 60 minute outdoor run. The researchers recorded improvements in mood alongside increases in anandamide and another endocannabinoid called 2-AG.
These findings support a connection between running, endocannabinoids and changes in mood. However, increased levels of these chemicals do not prove that they directly cause the runner's high. Researchers believe they may play an important role, but other biological and psychological processes are also likely to contribute.
Does Running Intensity Make A Difference?
Running intensity appears to influence the body's endocannabinoid response, although researchers have not identified a particular pace or effort level that reliably produces a runner's high.
Several studies have found that moderate intensity aerobic exercise increases circulating anandamide levels. This suggests that running at a steady, manageable effort may create conditions associated with some of the biological changes linked to the experience.
However, increased endocannabinoid levels do not guarantee euphoria. Individual responses vary, and researchers have yet to establish exactly how exercise intensity, duration and fitness influence the likelihood of experiencing a runner's high. There is therefore little reason to push yourself to exhaustion in pursuit of the sensation. Running at an intensity appropriate to your fitness is a more sensible approach than attempting to force a particular emotional response.
Does Everyone Experience The Runner's High?
No. Some runners describe experiencing the runner's high regularly, while others encounter it only occasionally or have never noticed anything resembling the classic sensation.
One difficulty in measuring its frequency is that the experience is subjective. What one person considers euphoria might be described by another as an ordinary improvement in mood, making comparisons between runners difficult.
Research has also identified differences in how individuals respond to exercise. A small study published in 2024 found that regular runners experienced greater improvements in mood after running than occasional runners, although the relationship with endocannabinoid levels was not straightforward.
These findings suggest that fitness, running experience and individual physiology may influence how people feel after exercise. However, there is not enough evidence to conclude that experienced runners are necessarily more likely to experience a runner's high.
Is The Runner's High More Likely On Race Day?
Race day can produce powerful emotions, particularly when runners are surrounded by enthusiastic spectators and thousands of fellow participants. The excitement of taking part in a major event can make the experience feel very different from an ordinary training run.
Crossing the finish line of a first marathon, achieving a personal best or completing a difficult challenge can also produce intense feelings of happiness and accomplishment. These emotions may resemble aspects of the runner's high, but they are not necessarily caused by the same biological processes.
There is insufficient evidence to establish that participating in a race makes the runner's high more likely. The atmosphere, anticipation and personal significance of an event can all influence how runners feel, independently of any exercise related chemical changes.
Can You Increase Your Chances Of Experiencing It?
There is no guaranteed method for triggering a runner's high, but research provides some clues about the conditions associated with changes in endocannabinoid levels.
Moderate intensity aerobic exercise has produced increases in anandamide in several studies. For runners, this suggests that maintaining a steady, manageable effort may be a reasonable approach, although it remains uncertain whether this makes euphoria more likely.
Building endurance gradually can also make running more comfortable. As fitness improves, maintaining a continuous effort may become easier, allowing runners to enjoy their surroundings and the experience itself without concentrating entirely on physical discomfort.
Some runners find that music, attractive surroundings or running with friends improve their mood. These can make running more enjoyable, but there is insufficient evidence to establish that they directly trigger the biological runner's high.
Rather than making euphoria the objective of a training session, concentrate on finding a style of running that you enjoy and can maintain consistently.
The Runner's High And Mental Health
The runner's high should not be confused with the broader mental health benefits of running. Although both involve changes in how we feel, a temporary episode of euphoria is different from the improvements in psychological wellbeing that can develop through regular physical activity.
Research has consistently found that exercise can help reduce symptoms of depression and anxiety. A major review published in 2026 examined evidence from numerous clinical trials and found that exercise interventions produced meaningful reductions in both, with aerobic exercise showing particularly strong benefits.
Running can also provide a break from everyday pressures, opportunities for social interaction and a sense of achievement as fitness improves. Spending time outdoors may add to the enjoyment of exercise, while working towards a personal goal can help build confidence and motivation.
These benefits do not depend on experiencing a runner's high. Someone who has never felt euphoria during a run can still gain considerable physical and psychological rewards from regular exercise. Running can support mental wellbeing, although it should not replace professional treatment when that is needed.
Enjoy The Run, Not Just The High
The runner's high remains one of the most interesting aspects of the relationship between exercise and the brain. Research has moved beyond the traditional explanation involving endorphins, with endocannabinoids now considered important candidates in understanding why running can sometimes produce feelings of euphoria, relaxation and reduced anxiety.
There is still much to discover, particularly about why the experience differs so widely between runners. What is clear is that enjoying running does not depend on experiencing a runner's high. Improved fitness, better mental wellbeing, friendships and the satisfaction of achieving personal goals provide plenty of reasons to keep running, whether that elusive feeling arrives or not.
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