I recently posted a social media post on the topic of stress and its impact on our ability to optimally recover from training loads. Given the flurry of interest, ongoing questions and requests for support I received afterwards, I wanted to provide an excerpt on the topic of stress from my Trail Running Guidebook. I feel that stress and its impact on our hormones is poorly understood, so I hope you find this article helpful.
I have found more and more frequently that many well-documented training theories are hard to implement with adults without triggering an overtraining complex, leading to unnecessary injury niggles, sick- ness, suppressed mood and more.
Stress: The fight-or-flight response
Stress is the body’s reaction to a physical, mental or emotional change in our normal, balanced state. In an ideal world, our body would deal with all stressors one at a time via the fight-or-flight response. Our body’s fight-or-flight response activates the nervous and hormonal systems when the stressor (the ‘tiger’) pounds towards us. The nervous and hormonal systems ensure that the heart and breathing rates accelerate; blood is relocated to the heart, lungs and muscles for movement; functioning of the gastro-intestinal tract is inhibited; and mobilisation of energy sources occurs. Then, once the danger is dealt with, we return to our steady state. However, there are two interesting things about the human stress response:
It is a one-size-fits-all mechanism. That is, the body cannot distinguish between different stressors, whether they derive from your workplace, family life, pain, other discomforts, environmental inputs, diet or even exercise.
Stressors compound. The accumulation of these individual stressors can lead to a chronic stress response in which the body remains in a heightened state of stress-induced arousal.
Hormones and stress: A tight link
The stress response is controlled by both the nervous and hormonal systems of our bodies. However, I have found that one of the most interesting impacts that stress has on us, especially as athletes, is how it affects our hormonal system. To understand the significance of stress on our hormones, we need to understand the incredible role our hormones are playing at every minute of the day. They help us to:
maintain a feeling of balance
feel recovered from training and daily activities
wake up feeling restored
maintain alertness during the day
feel emotionally stable
restore and maintain the musculoskeletal system
Healthy hormone function relies on pregnenolone, our ‘master hormone’. Pregnenolone is critical for the production of:
sex hormones – especially oestrogen,progesterone and testosterone
stress response hormones – especially cortisol, but also adrenalin and noradrenalin.
Each of these hormones is found in both females and males. However, oestrogen and progesterone are found in substantially higher amounts in women, while testosterone and growth hormone are found in significantly higher amounts in males.
OESTROGEN Oestrogen has more than 400 functions in the body and is the main female hormone. It shapes the uniqueness of our female bodies and emotions, makes us feel sensual, brings a glow to our skin, moisture to our eyes, fullness to the breasts and clarity to the mind. Importantly, it gives us the feeling of female energy and sensuality.
PROGESTERONE Progesterone reduces anxiety and has a calming effect on our mood. It helps us to feel happy and calm, increases sleepiness, helps to build and maintain bones, slows the digestive process and prepares a female for pregnancy.
TESTOSTERONE & GROWTH HORMONE Testosterone and growth hormone are produced by both males and females, although to a much lesser extent in females. Without testosterone, the body’s ability to repair musculoskeletal tissue is hindered. Testosterone is the main male hormone, and assists a male to feel masculine and energised, and creates muscle bulk and strength.
PREGNENOLONE STEAL When we are in a calmer state of balance, there should be ample master hormone, pregnenolone. The body should be able to make adequate amounts of our sex hormones, as well as the key stress hormone, cortisol. However, if stressors compound, such as through poor diet, exercise, insufficient sleep, lack of relaxation, and internalisation of emotional stress, we can fatigue our adrenal glands. When this occurs we effectively are entering a chronic state of stress. The need to produce vast quantities of cortisol overrides the production of our sex hormones, an occurrence that has become known as pregnenolone steal.
Living with chronic stress
Up until this point, I have inferred that stress is a negative occurrence. However, sometimes it can include positive events, making it harder to recognise the build-up of stress, the onset of pregnenolone steal and the sneaky slippery-dip into chronic stress.
Positive stressors include:
uplifting family occasions such as becoming a parent, birthdays, school sport or Christmas
travel and holidays
empowering work such as presentations, conferences and work travel
Negative stressors include:
physical activity that becomes forced and routine, without taking into account your need to recover – for example, continually harder days of training or heavy effort
poor sleep routines
extreme climatic events such as heatwaves
difficult emotional situations such as family illness or workplace stress.
Accumulating stressors in the context of inadequate physical and mental rest can lead to a chronically activated fight-or-flight response and can disrupt hormonal balance. Degeneration will begin to occur to our body’s tissues, increasing our risk of injury and poor wellbeing. These changes include: alterations to sleep-awakening patterns; gut irritability; suppressed appetite; weight changes; agitation accompanied by poor concentration; restlessness; muscle loss; decreasing bone density leading to stress fractures or joint issues; immune suppression; and overall fatigue. Furthermore, if you are finding yourself required to cope with too much stress then you may be at risk of long-term changes to your mind, body and playful spirit.
I cover these effects in more detail later in The Trail Running Guidebook in a chapter on Overtraining Syndrome. Further to this, the book is filled with information on the training principles I believe can enhance performance through adequate recovery.