For non-runners who don’t appreciate the appeal of a two-hour slog at 6am, know that running (and other forms of cardio) sometimes produces a powerful chemical hit that justifies comparisons with actual narcotics.
The body produces two feel-good substances typically associated with a runner’s high. Endorphins are the better-known one. These neurotransmitters are sometimes compared to morphine because of their ability to alleviate pain.
One theory is that they evolved to help hunter-gatherers chase down prey or escape predators by numbing the effects of blisters and other foot pain.
For runners, research suggests that longer runs – where you’re working hard, but not too hard – are a sweet spot for endorphin production. If you’re trying to jump-start a runner’s high, try a ‘tempo’ run.
After a good warm-up, try to run for around 20 minutes or more, while holding a pace that’s about a 6 or 7 on a scale of 10 (where 10 is an all out sprint).
Though endorphins were long believed to cause the euphoric feeling associated with a runner’s high, the theory has recently pulled up with cramp. Endorphins are too large to cross the blood-brain barrier and researchers now believe another substance is responsible for the elation you feel near the end of a run.
Endocannabinoids are essentially the same molecules responsible for getting marijuana users high, but they’re produced by the body.
Research shows that when cannabinoid receptors are turned off in mice, they run less. And in 2021, a team at the University Medical Center Hamburg-Eppendorf in Germany found that when the opioid receptors that bind to endorphins are switched off, runners still experience a high.
This supports the idea that cannabinoids are the better candidates responsible for a runner’s high.
In that study, participants ran for 45 minutes at a moderate pace. To experience that same high, aim for a consistently difficult pace where you struggle to maintain a conversation.
This article is an answer to the question (asked by Emily Mullin, Colchester) 'When does a runner's high kick in?'
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