Runner's High & Long-Term Mental Benefits of Exercise

Running can be addictive — in the best possible way.

Heading back from a coffee with Lil at the Chiltern Velo, I was feeling that familiar sense of clarity and joy: runner’s high. It was a perfect autumn day, with blue skies and crisp air, and I’d had a week full of inspiration. Lil had cycled to the café, which got me wondering: why do I feel this exhilarating rush after a run but not as often after a bike ride?

What is Runner’s High?

"Runner's high" is that wave of happiness, optimism, and energy that sweeps over you during or after a good run. Runners often describe it as a feeling of mental relaxation, physical ease, and sometimes even pain relief. But what causes this and why does it happen with running more than other sports?

When you head out for a run, your body goes through a series of changes: your breathing picks up, your heart rate increases, and blood flows rapidly to your muscles and brain. During this phase, the body releases a blend of brain chemicals—especially endorphins, endocannabinoids, dopamine, and serotonin—which together create a unique cocktail of euphoria.

1. Endorphins: Endorphins, known for their pain-relieving and mood-boosting effects, are released during intense aerobic activity, helping reduce pain and heighten euphoria. However, they don’t fully explain runner’s high, as they struggle to cross the blood-brain barrier. PET scan research has shown that while endorphins do bind in the brain, their influence on mood is subtle compared to other chemicals (Boecker et al., 2008).

2. Endocannabinoids: Unlike endorphins, endocannabinoids like anandamide cross into the brain much more easily, producing a calming, euphoric effect that’s often described as the primary factor behind runner’s high. A 2003 study demonstrated that high-intensity exercise significantly increases anandamide levels, resulting in effects similar to cannabis in terms of reduced anxiety and elevated mood (Sparling et al., 2003).

3. Other Neurotransmitters: Exercise also boosts dopamine and serotonin, key players in mood regulation and reward. These contribute to the overall sensation of joy and calm, enhancing the “high” feeling many runners experience.

The combination of these chemicals, triggered by intense, rhythmic exercise, creates a powerful mental lift. And when paired with a steady, repetitive activity like running, the mind can enter a “flow state”—a deeply immersive focus often tied to increased endocannabinoid release and felt more easily during activities like running than in complex or stop-start exercises (Csikszentmihalyi, 1990).

Why Don’t You Get the Same High from Cycling?

If you’ve ever noticed that runner's high is harder to achieve while cycling, you’re not alone. Here are a few reasons why:

1. Intensity and Impact: Running is a high-impact activity that requires more muscle engagement and intensity than cycling on flat roads or gentle inclines. Studies comparing runners to walkers found higher endorphin release in runners, emphasizing that greater intensity prompts a stronger chemical response in the brain (Harber et al., 1998).

2. Mental Engagement: When cycling, you’re often focused on balance, traffic, or terrain, which can make it harder to reach the flow state. Running, especially in a peaceful environment, encourages repetitive, rhythmic movement that can easily lull the mind into a meditative state, another factor in runner's high.

3. Muscle Dynamics: Running and cycling engage muscles differently, with running requiring more impact and ground contact. This difference may stimulate endorphin and endocannabinoid release more in running than cycling, as suggested by studies on the biomechanics of high-impact versus low-impact exercise (Laursen et al., 2002).

The Long-Term Mental Benefits of Exercise

Beyond the immediate benefits of runner's high, regular aerobic exercise promotes long-term brain health in powerful ways:

1. Improved Brain Function: Cardiovascular exercise increases blood flow to the brain, stimulating new blood vessel growth and supporting brain health.

2. Neurogenesis: Exercise can even produce new brain cells, particularly in the hippocampus, which is associated with memory and learning. This has been linked to a decrease in cognitive decline as we age.

3. Mental Resilience: Consistent exercise has a powerful anti-depressive effect. As neuroscientist Dr. Linden explains, “Exercise blunts the brain’s response to physical and emotional stress.”

4. Enhanced Cognitive Skills: Regular exercise improves working memory, focus, and cognitive flexibility. This translates to better problem-solving skills, creativity, and overall brain performance.

For a runner's high, it usually takes a continuous, high-intensity, rhythmic activity like running to trigger that euphoric wave of chemicals. While it’s not impossible to experience a similar effect while cycling, it may require a longer, more intense ride—like a challenging hill climb in The Chilterns (!) or a sustained sprint. If you’ve read my cycling story you will learn that I am only just new to ‘full-effort’ cycling this year, which is why I have experienced it less frequently from cycling than running!

Ultimately, runner's high is just one of the many ways running rewards the body and mind. But whether through running or another activity, the commitment to movement is a gift to the brain and body that pays dividends in both the short and long term.