Stress Can Cancel Out Your Fitness

Sara Givens remembers practically every day of training for her 70.3 in 2018, because they all began in exactly the same way. She would wake up at 4:15 a.m., brush her teeth, and grab her duffle bag on her way out the door to the pool. “The dawn-patrol swims were the only way I could get quality pool time. All I had to do was just make sure I went to bed early and it wasn’t too bad.” The rest of the day was a blur of work projects, social commitments, and sometimes more training. She was exhausted but hanging on–until her father got pneumonia. “I was terrified. I just wasn’t ready to see him that sick. When I felt like I was losing it, I would go for a run or get on the bike. I thought it was the right thing to do for the stress.” But, as she was getting closer to race day, Givens didn’t feel ready. She felt wrecked. “I didn’t understand how I could actually get slower through my training, but it happened. From the second I hit the water on race day, I knew it wasn’t going to be pretty.”

She struggled to finish the race and when she couldn’t get the fatigue out of her legs even weeks later, she decided to take time off from training completely. She spent most of the next year worried about not just her dad, but also herself. What went wrong? Wasn’t she supposed to push hard through the struggles? And more importantly, how could she feel like herself again?

How the brain and body respond to stress

If we told Givens that her performance was suffering due to a fracture in her femur, she likely would have immediately stopped training and started recovering. Unfortunately, her “fracture” was one that she couldn’t see because it was happening inside her body in a system that is more important to an athlete than any other: the endocrine system. Composed of glands and hormones that act as chemical messengers, the endocrine system functions as the master regulator of all biological processes in the body from metabolism to brain development and from reproduction to blood sugar regulation.

Everything we do, see, think, smell, touch, and experience is processed by a gland in the brain called the hypothalamus. The hypothalamus then determines the course of action and signals the pituitary gland, another small gland in the brain, to send out the hormones. These hormones flow through the entire body and interact with target cells that have compatible receptors to alter or adjust the functionality of organs according to the directions given by the hypothalamus. This means that the endocrine system can do things like send out more thyroid hormone to regulate body temperature in cold weather and drop levels of testosterone when men do not take in enough calories or train too hard.

Dr. Nicky Keay, a sports endocrinologist, lecturer in medicine at University College London, and research fellow in the department of sport and exercise sciences at Durham University, underscores the importance of the endocrine system for athletes, “Why do you get fitter? You train because you think you’re going to improve, but why does exercise have this effect? That is thanks to your hormones. They are the conduits to what you do on the outside like training, sleep, nutrition–and how that gets translated to your brain and muscles.” This is good news for those of us training hard and hoping that our body responds, but it’s bad news for those of us who have been pushing too hard and hoping our body won’t notice. “Your hypothalamus sees it all. There are no secrets,” said Dr. Keay.

RELATED: Triathletes Suffer Better – Unless They’re Stressed

Everyone has limits (even you)

You might think that there is a difference between the stress from racing a half-iron distance triathlon and the stress from getting fired from your job—even if you are doing that half-iron precisely because you got fired—your hypothalamus does not agree. The sensitivity of the endocrine system means that your hypothalamus can not distinguish between types of stress, since research shows that it is designed to react to all by releasing stress hormones like cortisol. “Why should it distinguish? They are both a threat,” said Dr. Keay. The key is to have adequate recovery for these stressful events, so that the body and mind can repair and even adapt when necessary. Studies show that without enough recovery time, the body eventually becomes dysregulated as it struggles to keep functioning despite the repeated threats.

Whether we find it “enjoyable” or “unenjoyable,” the truth is that stress is both additive and dangerous when chronic. Multiple studies show that there is only so much stress, whether physical or mental, that we can add to our lives before the whole system breaks down. Whether we experience metabolic downregulation, blood sugar issues, or even RED-S (Relative Energy Deficiency in Sport), the mounting pressure on the endocrine system to adapt is responsible. 

RELATED: Despite Increased Awareness, RED-S Still a Major Problem in Endurance Sports

Some of the other symptoms that athletes might be headed for trouble are fatigue, sluggishness, loss of a period for women, and erectile dysfunction for men. “We have to talk about men not having a morning erection,” said Dr. Keay, “because the more we talk about it, the more they will know that this is a sign that something is wrong.” Finally, there is a real threat of Overtraining Syndrome, which research shows is the result of chronic dysregulation of the endocrine system and the subsequent negative effect on all the body systems it controls.

How to optimize endocrine function

Athletes should be thankful for the body’s ability to compensate for all of the stress that they put it through, but it’s difficult to be thankful when struggling with heavy legs and fatigue on a run. However, learning to embrace the limits of the endocrine system can actually make us into better and smarter athletes. Every single day we have the opportunity to make decisions that can either help us to stay far away from those limits or drive us right into them. For a long and healthy triathlon career, Keay recommends a typical “day in the life” checklist for optimum endocrine system function.

It starts with sleep

“If you’re going to get one thing right, let it be sleep. Sleep is the key thing to align all internal clocks. When they go out of sync is when you start to have problems.”  

Food is crucial within one hour of waking

“Fasted training early is the one key thing that will ruin hormones because when you wake up, your cortisol is high. You have to break that fast and eat something. You can sleep an extra 20 minutes, but your hormones are going to suffer.” 

RELATED: The Pros and Cons of Fasted Workouts

Keep the good nutrition going

“Always go into any sort of training session with some fuel on board. If you can’t get a meal in about an hour and a half before the session, you need to have some kind of banana or a cereal bar before starting the session. After the training is finished, either get a meal in 20 minutes or have a favorite shake with protein and carbohydrate until you can get a meal in.”

Monitor your mindset

“Even thinking about putting pressure on yourself by thinking, ‘I should be restricting what I am eating’ or ‘I need to be training more’– that in itself, even without following through, that thought process is enough to alert the hypothalamus.”

Fuel up during training

“During training, pick a slower release carb if possible, and keep up the intake. Even if you’re totally topped up with glycogen, you’re going to run out and you don’t want to put that kind of stress on the body.”

RELATED: Triathlete’s Complete Guide to Nutrition and Fueling

Or choose not to train at all

“Sometimes on heavy stress days, when you’re exhausted from life issues, it’s better to not train. If you go and push yourself, you’re likely not going to get much out of it. Not only that, but you may also be affecting your ability to gain training adaptations from the next time you go out there. As an athlete, when you decide to rest, that is a positive. That may not be the case for people in all populations in the world, but it is the case for endurance athletes.”

Never skip a rest day

“You have to have at least one rest day per week, but it has to be a true rest day, not just a rest day from your sport. Active rest is not rest. That’s rubbish. That’s not the definition of rest and certainly, your hormones will not interpret it as such, which is more important.” 

RELATED: Do I Have to Take Rest Days?

Athletes who consistently use training to compensate for the emotional discomfort that comes from stress can find it incredibly challenging to change habits and embrace doing less. It requires athletes to recognize that the perception that training is always a net positive is not correct and there can be real consequences from continually adding pressure with more workouts. Sometimes, all that’s needed is to not do the hard intervals and instead go for a light social ride with friends or a jog with your dog instead of a more serious run. But, if you feel that you are unable to step away from adding more training or can’t back off when necessary, even when you know that it is becoming harmful to you, it may be time to seek the help of a qualified mental healthcare practitioner. 

While it’s impossible to remove or decrease stress from all areas of life, athletes can control certain aspects of their training, nutrition, and lifestyle that can mitigate the damage. If you’re feeling overwhelmed or exhausted, instead of getting on the bike, try putting that effort into making time for a decent breakfast or getting to bed an hour earlier. You’ll be setting yourself up for a great workout tomorrow and probably an even better performance in the week ahead. Respecting your limits can actually set you free.

RELATED: Mental Health Resources for Triathletes

Jill Colangelo is a writer and researcher of mental health and ultra endurance sport. She has a BA and ALM in psychology and is a former triathlete and ultramarathoner.