David wasn’t sure how much longer he could hold on. He was deep inside himself, pushing his tired, bruised body through the pain, his determination stronger than anything else. Though his body screamed at him to stop, he dragged himself through the exhaustion, his mind pulling him toward the finish line.
Each minute, he is forced to decide: listen to that nagging, exhausted voice within him, or hold on just a little longer. How much longer can he drive himself through this, or is this pain he can no longer ignore? David is deep inside the pain cave.
Popularised by ultrarunning legend Courtney Dauwalter, the ‘pain cave’ describes the point in endurance running when exhaustion hits, doubt creeps in, and your body screams at you to stop. This is a critical point in the ultra community because how you react to it can determine your race.
Courtney Dauwalter told the BBC: “The pain cave is where I go when it physically feels like I can’t take another step. It’s a visual I have of this space in my brain that I go to with a chisel, and I just go to work on making it bigger, which helps to stay mentally tough in those difficult moments — and makes my capacity for suffering bigger.”
So do experienced ultrarunners like Courtney Dauwalter feel less pain? Or do they just know how to respond to it differently? What’s the difference between pain we can push through and pain that we need to listen to?
Let’s First Look at Pain.
Pain is something you quickly get used to when you run. Blisters, sore muscles, hurting knees, and lost toenails become the norm when you’ve spent enough time endurance running. Knowing which pain you can push through and which signals real damage could be the difference between finishing and going to bed or finishing and ending up in hospital.
The International Association for the Study of Pain (IASP) defines pain as an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage. This definition recognises that biological, psychological, and social factors influence pain.
Pain is not simply a direct measurement of damage. Two runners with similar physical problems may report different pain levels, and the same runner may experience the same sensation differently depending on expectations, attention, stress, and context.
A 2026 scoping review of 17 studies on ultrarunners’ mental responses to pain found that runners may use both associative strategies (listening to the body) and dissociative strategies (thinking of something else). It also found that runners often expect and accept pain, but the effects of these psychological responses on actual race performance remain uncertain.
Why did that mile feel so long?
Your perceived exertion is a judgement of how hard the exercise feels overall, relative to your current capacity. It is your subjective view of the pain you’re experiencing or how much effort you are applying at that time.
Perceived exertion reflects more than breathing or heart rate alone. It is influenced by exercise intensity, muscle sensations, temperature, hydration, psychological state and how much capacity the runner believes they have left. Perceived exertion is ‘why did that mile feel so much longer than my first few miles?’ Many things come into play, but it’s how you view the pain and effort you’re putting your body through.
This makes it particularly valuable in ultrarunning. Pace and heart rate can be affected by hills, heat, altitude, accumulated fatigue and other conditions. Perceived exertion offers another way to judge whether the current effort is sustainable, whether I can keep going, or whether I need to stop.
The key point is that perceived exertion is not the same as pain. A runner can work extremely hard without experiencing much pain, or have a painful blister while running at a relatively easy effort.
Okay. I’m Tired Now.
Fatigue is a decline in your ability to produce or sustain a desired level of physical or mental performance, or, as Ed Sheeran once said, “When your legs don’t work like they used to before.”
As exercise continues, the body and brain change in ways that make it harder to maintain the same pace, force output, or concentration. This can magnify pain you may have been able to withstand earlier in the race.
Sports science commonly distinguishes between two interacting forms of fatigue:
Peripheral fatigue: Changes occurring in the muscles and other parts of the neuromuscular system involved in producing force. During an ultra, a runner may find that their legs can no longer produce the same power on a climb or control their body as effectively on a descent.
Central fatigue: A reduction in the nervous system’s ability to drive muscle activation, along with other changes that affect voluntary performance. Prolonged exercise, mental strain, and sleep deprivation can also make concentration and decision-making harder.
The important distinction is that pain is an experience, perceived exertion is a judgement of effort, and fatigue is a change in your capacity to perform.
Importantly, not all pain during an ultra should be treated as normal discomfort. New, sharp, or worsening pain; a sudden change in gait; or pain accompanied by other concerning symptoms warrants stopping and appropriate assessment.
For example:
David starts a 100-mile race; early on, around mile 20, he’s ascending a mountain, breathing heavily, legs pumping beneath him. He feels a burn in his quads and hamstrings as he climbs, but no significant pain. This is high perceived effort, little pain.
As David hits the halfway mark, pain and fatigue are beginning to accumulate. He develops sore quads and a painful hotspot on one foot. His muscles have less capacity for sustained work, and maintaining the same speed now feels harder. Even though a mile is the same length, each mile feels longer and harder to complete. This is high perceived effort, rising pain, and rising fatigue.
At mile 85, David is experiencing all three at once: pain, high perceived effort, and fatigue. Each mile feels longer than the last; darkness and sleep deprivation make navigation and decision-making harder, and pains that felt manageable before feel worse.
It’s all about your perspective.
A runner’s ultra experience isn’t determined solely by what is happening physiologically. It also depends on how they interpret sensations and respond.
- Pain asks: What am I feeling, and what might it mean?
- Perceived exertion asks: How hard am I working right now?
- Fatigue asks: How has my capacity to keep going changed?
A runner might see familiar muscle soreness as something they can manage, ease up to save energy, eat more, and keep going. But sudden, sharp pain could mean something is wrong and may be a reason to stop, no matter how tough they feel.
The 2026 scoping review of ultrarunners’ mental pain responses is especially relevant here. It found evidence of pain acceptance, internal dialogue and distraction among ultrarunners, but concluded that more research is needed to establish how these strategies affect race performance.
This is an important qualification: accepting pain psychologically does not mean the body is no longer under strain, and feeling capable of continuing does not guarantee that continuing is safe.
Can you train your brain?
So, can I be like Courtney Dauwalter and thrive inside my pain cave? The main takeaway is you need to know your body and understand what is normal and what is abnormal. Only then can you know when you can carry on or when it’s an issue.
However, there are small ways you can train your brain to push through that barrier that might take you a few more miles and show you what you’re capable of:
1. Practise noticing sensations without immediately reacting
During an ordinary, easy training run, notice discomfort and describe it neutrally: “My calves feel tight” or “My breathing has increased.” Rather than immediately labelling the experience as unbearable, observe how it changes. This approach draws on mindful awareness and acceptance. It is not a reason to ignore worsening pain or push through a potential injury.
2: Develop useful self-talk
Choose short, realistic cues before a difficult session. For example, “Relax my shoulders,” “One hill at a time,” or “Keep the effort controlled.” A 2015 meta-analysis of 32 sports studies found a moderate positive overall effect of self-talk interventions on performance.
Psychologists offer great tips when it comes to self-talk: Addressing yourself as “You” or calling yourself by name (known as distanced self-talk) creates psychological space. Instead of saying “I can do this,” saying “Sarah, you’ve got this” triggers social and relational brain systems to calm stress. Positive self-talk triggers dopamine release, which sharpens focus, boosts energy, and improves decision-making.
3. Build confidence through appropriate training
Gradually build your endurance and practise race-specific challenges under controlled conditions. Familiarity with prolonged effort, fuelling, hills and night running can make race demands less unfamiliar and help you develop confidence in your ability to cope.
Yes, you can practise accepting discomfort and change how you respond to it. But learning to accept pain is not the same as eliminating pain.
CITATIONS
1. International Association for the Study of Pain (IASP)
The internationally recognised pain definition and accompanying explanation of how biological, psychological and social factors influence pain.
IASP terminology and definitions
2. American College of Sports Medicine (ACSM)
Explains rating of perceived exertion and its use alongside physiological measures of exercise intensity.
What Is a Normal Rating of Perceived Exertion During Maximal Exercise Testing?
3. Central and Peripheral Fatigue in Physical Exercise Explained: A Narrative Review (2022)
A peer-reviewed overview of the multifactorial mechanisms involved in exercise fatigue.
Read the review on PubMed Central
4. Mental Pain Responses of Ultramarathon Runners: A Scoping Review (2026)
Delalay and Hotz Boendermaker, Sports, 14(2), 72. Directly relevant to your magazine’s focus on the psychology of pain during ultramarathons.
Read the full peer-reviewed paper
5. The psychology of ultra-marathon runners: A systematic review (2018)
Roebuck and colleagues, Psychology of Sport and Exercise. A broader review of ultrarunners’ motivations, mood, pain perception and cognitive processes.
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