Let me tell you an embarrassing story.

In my freshman year of college, we had an exhibition tournament for some of the donors of our tennis program.

I played line 1 on the stadium court against the assistant coach at the time. About 40 donors, sipping cocktails, drinking sweet tea, sat in the shaded observation area on the side of the court.

When the match started I didn’t know what was happening. The serve I had practiced thousands of times? Consistently flew long or hit the net at a pathetic pace. The heavy, topspin balls that I was able to generate without issue during practice? Gone. Poof. No longer available to me.

“What is happening?” is a consistent thought that I remember. It was as if someone else had taken control of my body and my brain wasn’t functioning how it normally would. My attention kept continually shifting to donors on the side of the court. Profuse sweating. Strange physical tension in my body.

I think I lost 0–6, 0–6, in what was, at that time, a supremely humiliating performance.

Maybe it was somewhere then that my curiosity about mental performance and applied sport psychology started. Perhaps you’ve experienced something similar—maybe not as extreme—but maybe to the point where while reading about my experience you, too, began to feel a little too uncomfortable.

If you’re a little like me, perhaps you’re curious. Why do experiences like this happen? And how can understanding the mechanisms stop it from happening again in the future?

That’s what we’ll cover today.

The experience I recounted to you was basically the activation of my fight or flight or sympathetic nervous system. But this isn’t just about somatic symptoms (or experiences in the body). It all begins with appraisal; or, in other words, how you interpret the situation.

In my case, I was 17, in a new country, on a new college team, surrounded by countless new teammates, coaches, and supporting characters, playing line 1 in an exhibition match. I probably appraised that event as hyper important.

I need to perform well here or else…. the donors won’t think much of me… the assistant coach won’t value me joining the team… my teammates won’t like me. You know, that kind of thing.

Psychologists call this cognitive appraisal—and it has two parts. The first is primary appraisal. It’s where an individual might ask themselves: “Is this situation a threat or a challenge?” Then is the secondary appraisal: “Do I have the resources to appraise that threat?”

So, I clearly was threatened by the scenario, or, at least, I saw it in that way. And worse, after perhaps an early double-fault or bunch of characteristic unforced errors, I was probably also answered the second question: “No, I don’t have the resources currently to handle it.”

Similarly, if you appraise or interpret matches, tournaments, leagues, as threats—”If I lose this, everything’s going to be terrible. I’ll lose the respect of others. People won’t like me.”—it can kick off a cascade. But if you appraise it as a challenge: “This is a tough scenario, but I’ve trained hard for this and I know that viewing it in such life-or-death ways is not conducive to me performing my best.”—you may get a little more physiologically aroused, but you’ll most likely stay in control.

Once I appraised the situation as threatening, things escalated inside of my brain (I hope you don’t mind, I’m going to use myself as a personal example here because I started with my own experience, but I trust you’ll be able to transplant it onto yours).

Specifically my amygdala, the part of our brains that processes fear and emotion, sent out distress signals to my hypothalamus. The hypothalamus acts a sort of control center connecting different parts of our brains to our bodies. In reaction, it kicked off two parallel systems:

Through the SNS, the hypothalamus sends signals via the spinal cord to the adrenal medulla, telling it to release both epinephrine (adrenaline) and norepinephrine. That’s why within seconds you feel your heart racing, breathing speed, and other physiological symptoms.

At the same time, the HPA axis sets off a hormonal chain reaction: the hypothalamus releases corticotropin-releasing hormone (CRH), which in turn tells the pituitary gland to release adrenocorticotropic hormone (ACTH, which in turn tells the adrenal cortex to release cortisol. Yeah, a lot of stuff goes on up there.

Cortisol can be useful in the short term as it helps provide glucose to our muscles, but over time it can also increase anxiety, narrow attention, and interfere with working memory control.

In short, my body was preparing to survive an attack, not execute a second serve (no wonder I double-faulted so many times).

So, after that short psychology session, here are the impacts of the SNS and the HPA-axis kicking off.

The first is that heart rate and blood pressure spike: All of this prioritizes large muscles, and isn’t the best for fine motor control—like hitting a serve or the delicate touch required for a touch volley.

Breathing becomes shallow and rapid: Can lead to dizziness and also hyperventilation.

Muscle tension increases: As mentioned, gross motor skills are okay, but the finer components tend to be corrupted.

Cortisol floods the body: Amplifies threat sensitivity and can disrupt cognitive flexibility.

This explains why even experienced players can feel like we “forgot how to play” in pressure moments. This system, which is the result of millions of years of evolution, is designed to help us survive in life-or-death scenarios, not put together the mental resources for putting a forehand into the court. In other words, it actively works against performance in complex motor tasks.

It’s not that you’re “weak” or that you “don’t have the killer instinct” or that you’re not “mentally tough,” or all the other kinds of bullshit that tennis coaches clueless commentators will say… it’s that your brain and body are flooding you with survival-mode signals at the exact moment that you need mental flexibility.

I know I have taken you in-depth regarding what actually happens when someone experiences the flight or fight response… but the next question you may be wondering is: “What can I do about it?”

While we can’t fully stop the body’s stress response, we can definitely make an impact on how we manage it.

The first technique is to shift our appraisal of the event. If you recall, when I was told I’d be playing Line 1 on the exhibition coach against the older assistant coach, I went into a defensive mental posture. I placed excessive stress on myself. “I have to win this.” “If I don’t play well, what will they think of me?” “I need to win so my teammates will respect me.”

In retrospect, it’s easy to pick up a few problems with this appraisal—or interpretation—of this event. In contrast, viewing the event as an exciting opportunity to demonstrate my skills would have been more conducive to my playing my best. Instead of it being a threat to my identity and place in this new team, I should have viewed it as what it was: just a tennis match, but one with interesting upsides. That being said, I know it’s easy to make this pronouncement in the future. While in the moment, I didn’t have the mental skills to view things this way. (Which is where work with a sport psychology professional comes in, by the way.)

I could have also seen the increasing level of arousal and anxiety in my brain and body as indicative of my body preparing me for performance instead of catastrophe. Research in sport psychology consistently shows that elite athletes view anxiety as facilitative instead of debilitative.

As we’ve covered, this threat appraisal kicks off the sympathetic nervous system, which communicates with the hypothalamus, amygdala, HPA-axis to flood our bodies with epinephrine, norepinephrine, and cortisol. This is what creates the mental and physiological symptoms of fight or flight.

What is one remedy?

To activate the parasympathetic nervous system (PNS). The PNS is responsible for bodily regulation and can impact heart rate, blood pressure, and resulting racing thoughts and challenging emotions. Think of it as the body’s brake pedal which can be used to calm the system. And… how do we activate it? Well, you have quite a few options. The first would be to learn to box breathe. The next would be to learn to modulate arousal through something like a progressive muscle relaxation before the match. Another option would be to start building mindfulness and attentional control as a skill, focusing on things like body scans and diaphragmatic breathing, so that you have more of an awareness of how aroused and anxious you’re becoming.

This response of fight or flight is very human. In fact, I can almost (not certainly, but almost) guarantee that one of your ancestors, either hundreds, thousands, or millions of years ago, was able to benefit from this wiring enough to be able to survive a harrowing situation so that they were able to subsequently pass on their genes… to you. So, reflect on that for a bit.

That being said, knowing that your body isn’t betraying you, and that it’s just responding to how your brain is interpreting the situation, should give you a foothold to dig into. We can’t control everything on court and the competitive environment, but we can work on how we appraise pressure moments, how we engage the body’s calming systems (PNS). And with training and awareness, you can turn this very human reaction into an ally, not an enemy.

Disclaimer: I am not a licensed psychologist, mental health counselor, PsyD, or clinical PhD. I am currently pursuing a Master’s degree in Sport, Exercise, and Performance Psychology and am a sport psychology practitioner-in-training, working toward the Certified Mental Performance Consultant® (CMPC®) credential provided by the Association for Applied Sport Psychology (AASP). My work focuses on applied, non-clinical mental performance consulting, using evidence-based techniques grounded in psychology, sport science, and applied sport psychology to help athletes enhance focus, manage pressure, build confidence, and improve performance. I do not provide mental health counseling or clinical therapy. When needed, I will always refer clients to licensed mental health professionals for concerns beyond the scope of performance consulting. I have over 20 years of experience in tennis, including as a player, collegiate and professional coach, and director of programs. I am certified by the Professional Tennis Registry and am a member of Tennis Australia. My goal is to bring athletes the best research-backed insights to support long-term development and performance. If you are a researcher or practitioner and feel I’ve misunderstood or misrepresented any concept, I welcome you to reach out, and I will gladly review and issue corrections if appropriate.