Why Do You Get Nervous Before Something Big?

The night before a presentation. The hour before a job interview. The seconds before you walk out on stage.

Your heart rate rises. Your palms are a little damp. Your mind keeps rehearsing scenarios, most of them the same one going wrong in slightly different ways.

You know this feeling. Almost everyone does. But why does it exist, and why is it so predictably attached to things that matter?

The HPA Axis: Your Ancient Alarm System

Pre-performance anxiety activates the hypothalamic-pituitary-adrenal axis — the body’s primary stress response system.

The process: the hypothalamus detects a threat (or an anticipated challenge) and signals the pituitary gland, which releases ACTH into the bloodstream. ACTH reaches the adrenal glands, which sit atop the kidneys, triggering the release of cortisol and adrenaline (epinephrine).

These hormones produce the familiar physical symptoms:

• Heart rate increases, pumping more blood to muscles
• Breathing rate rises, increasing oxygen delivery
• Blood is redirected from the digestive system to skeletal muscles — this is why you lose appetite and feel the stomach sensation
• The liver releases glucose for immediate fuel
• Sweating increases for temperature regulation
• Attention narrows and vigilance heightens

This is preparation. The body is mobilizing resources for a significant event. The problem: it doesn’t distinguish between a tiger and a presentation to your team. The physiological response is the same.

The Same State, Different Interpretation

Here is the core finding from research by Alison Wood Brooks at Harvard Business School.

Brooks told subjects to either calm down before a stressful task (“I am calm”) or to reframe their anxiety as excitement (“I am excited”). She then measured their performance.

The calming instruction was largely ineffective — and sometimes harmful. Telling yourself to be calm when you’re physiologically aroused is a mismatch: the body is in high gear and your instruction asks it to idle. The body doesn’t immediately comply.

The excitement reframe worked. Subjects who told themselves they were excited performed better on math tests, karaoke singing (judged by strangers), and negotiation tasks than subjects who told themselves to calm down.

The reason: anxiety and excitement share nearly identical physiological profiles — high arousal, elevated heart rate, activated nervous system. They differ primarily in their valence: anxiety is high arousal + threat appraisal (something bad might happen), while excitement is high arousal + opportunity appraisal (something good might happen).

Reframing doesn’t require suppressing the arousal — it reinterprets what the arousal means. The body is still revved up. Now the mind frames that state as useful rather than threatening.

When Nerves Help Performance

The relationship between arousal and performance follows what’s known as the Yerkes-Dodson curve: performance improves as arousal increases — up to a point. Beyond that point, additional arousal hurts.

The shape of the curve depends on task complexity:

• For simple tasks (sorting objects, repetitive physical actions), the optimal arousal level is relatively high — more adrenaline is more or less just more fuel.
• For complex tasks (writing, problem-solving, anything requiring creativity or fine motor control), the optimal level is lower. High arousal narrows attention and impairs the flexible, wide-ranging thinking these tasks require.

This is why a moderate amount of nerves before a piano recital or a chess match tends to help, but extreme anxiety degrades performance. The question isn’t whether to eliminate nerves — it’s whether the arousal level is calibrated to the task.

The Physical Mechanism of “Choking”

What happens when nerves go wrong?

Sian Beilock’s research at the University of Chicago documented a specific failure mode in skilled performers under pressure: explicit monitoring.

Skilled performance — whether hitting a baseball, playing guitar, or driving a car — is largely automated. The movements are stored as procedural memory and executed with minimal conscious supervision. When performance is going well, consciousness is mostly watching, not driving.

Under extreme anxiety, performers revert to conscious step-by-step monitoring of movements that should be automatic. They start thinking about the mechanics of the swing or the placement of their fingers. This interferes with the automatic system. The result: performance degrades to beginner levels.

This is why choking under pressure often looks like a failure of skill, when it’s actually a failure of process — anxiety triggering an unhelpful mode of self-supervision.

Why the Anticipation Is Often Worse

A consistent finding: people’s physiological stress response peaks not at the moment of the stressful event but before it.

Cortisol and adrenaline levels tend to rise in anticipation and then begin dropping once the event is underway. The dread is concentrated in the waiting.

This pattern has an evolutionary logic: the body needs to mobilize resources before the challenge arrives, not after. But for modern performance contexts — where the “threat” is social evaluation rather than physical danger — the timing creates a miserable experience. All that preparation physiology fires before the event, leaving you amped up and waiting with nothing to do with the energy.

The practical implication: the period just before a performance is often the worst it will feel. Once you start, things usually get easier.

What Actually Helps

The research converges on a few things:

Reframe, don’t suppress. “I am excited” beats “I am calm” for high-stakes performance. Go with the arousal rather than against it.

Expressive writing before the event. Research by Beilock and colleagues found that students who spent 10 minutes writing about their worries before a high-stakes exam performed better than those who didn’t. The hypothesis: writing externalizes the anxiety, reducing its occupation of working memory during the task itself.

Controlled breathing. Slow exhalation (longer out-breath than in-breath) activates the parasympathetic nervous system and reduces heart rate. This doesn’t eliminate arousal but modulates it — shifting the balance slightly away from fight-or-flight.

Process focus vs. outcome focus. Athletes and performers who focus on executing the process (this specific movement, this specific breath, this phrase of music) rather than on outcome (what if I fail?) show less performance degradation under pressure.

Preparation. The most reliable treatment for pre-performance anxiety is mastery. The more deeply a skill is embedded, the more resilient it is to the disruption of arousal.

Your heart is pounding because something matters.

That’s not a malfunction. That’s information.

The question is what you do with the information once you have it.