For many runners, training is a way of relieving stress.

However, it’s important to look at how your body deal with stress and how training affects it. Failing to pay attention to this process may be detrimental and can contribute to an increased risk of injuries, illnesses, and poor performance.

How Does Stress Work?

Stress is a hormonal process in the body, caused by stimuli that the body register as threats. While stress may be necessary for survival, being in a prolonged state of stress can be detrimental to our health and impact sport performances.

Stress are often divided as acute (short-term) or chronic (long-term). While our body tend to be great at recovering from short-term stress, research has shown that chronic stress has been linked to poor health, depression, reduction in sports performance and increased foot injury risk.

Stress is a response to both external and internal stimuli operating through the “slow” hormonal signaling processes. This means that you’re going to experience stress relative to your training volume and intensity, meaning that running less (either as a reduction in volume, intensity or frequency) can improve your health and performance.

Stress has a general effect on the body, having negative effects across a wide variety of systems and domains. Some key markers that are affected include [1]:
· Plasma glutamine levels
· Plasma creatine kinase activity
· Plasma Urea
· Plasma hormones (especially in the antagonism between catabolic and anabolic hormones)
· Blood lactate profiles
· Immunological markers (especially serum leukocyte subset counts)
· Heart rate
· Blood pressure
· Neurotransmitter saturation and uptake

Running Can Contribute to Stress Levels

We all know the many benefits of running. Ideally, a productive (and healthy) run is supposed to improve your overall health and fitness level, increase your overall energy level, as well as make you feel incredibly happy with the release of the “happy” hormones.

However, stress caused by other aspects of our lives may make a run less ideal. In our hectic lifestyles, it is not surprising that we are constantly exposed to different kind of stress. Be it from a heavy workload, a bad relationship or from overtraining, our body responds to all kinds of stresses the same way.

Whether you run to compete or run for enjoyment, that stress relief you’re seeking may result in adding more stress to your body. Training volume – as measured by the pace and mileage – can be a contributing factor to adding to your existing stress levels. According to Selye’s widely-accepted stress-model, all training requires you to undergo the cycle of ‘stress – recover – adaptation’ in order to improve your muscular strength, joint health and nervous system output [2].

While we may need to put our body under some physical stress in order to improve, an accumulated amount of stress will turn detrimental. Runners running with high stress levels, often find themselves experiencing an increased level of fatigue and unable to reach their optimal performance. This is the result of an overtaxed body that is no longer able to recover from the stress of running.

What are the Key Dangers of Stress?

Stress is not a problem by itself, we are designed to deal with stress. However, the accumulation of too much stress from any source is a real problem for your health and performance. Chronically-elevated stress levels impacts muscular recovery and mental health through hormonal signaling.

This is a possible mechanism by which exercise contributes to overtraining. According to Margonis et al [3], overtraining is a non-specific set of physiological changes that result in poor sport-specific performance. The problem with this classification, however, is that reference values for “normal” levels of tolerance and resting/healthy levels are not available. “Excessive” stress is defined only by its symptoms.

Lucile Smith [4] linked these problems to the function of Cytokines in the immune system, suggesting that generalized inflammation and oxidative stress are common results of overtraining and chronically-elevated cortisol levels.

The link between the two is substantiated further by Smith’s later work, which discussed the immune-suppressive effects of exercise training in general, with leukocyte levels for regular individuals actually being greater than athletes who have recently trained [5]. Whether this indicates the general suppression of the immune system or an increased Leukocyte efficiency is uncertain, but activity of various neutrophils in the blood are also lower in athletes, suggesting that intense training can have chronic, detrimental effects on health and immunity.

Elevated cortisol levels can reduce performance through reduced recovery capacity. Cortisol interrupts the recovery processes by antagonizing the anabolic processes: corticosteroids suppress the production and uptake of key recovery/growth compounds like testosterone, somatotropin, IGF-1 and Insulin. This also contributes to insulin resistance and Type-II diabetes.

Excessive stress can also reduce performance in races. Cortisol is mediated and attenuated by adrenaline, but an excess of stress contributes to over-production of adrenaline, resulting in huge competition anxiety. While small amounts of excitation and anxiety can improve performance by improving cognitive focus and exciting the nervous system, the levels associated with chronic stress are more likely to cause poor technical performance and biomechanical positions [6].

This is going to show up rapidly in a variety of technical errors and poor strategic choices.

Closing Remarks

Stress isn’t a trivial part of your life: it affects the way you live, work and run. Run while being stressed increases the chance of injury and impedes recovery. Take some time for yourself, aim to have some stress-free periods by making adjustments to your stress processes can help you achieve better mood, better health and even better race time!

References

[1] Urhausen, Axel, Holger Gabriel, and Wilfried Kindermann. “Blood hormones as markers of training stress and overtraining.” Sports medicine 20.4 (1995): 251-276.

[2] Selye, Hans. The stress of life. 1956.

[3] Margonis, Konstantinos, et al. “Oxidative stress biomarkers responses to physical overtraining: implications for diagnosis.” Free Radical Biology and Medicine 43.6 (2007): 901-910.

[4] Smith, Lucille Lakier. “Cytokine hypothesis of overtraining: a physiological adaptation to excessive stress?.” Medicine & Science in Sports & Exercise 32.2 (2000): 317.

[5] Smith, Lucille Lakier. “Overtraining, excessive exercise, and altered immunity.” Sports Medicine 33.5 (2003): 347-364.

[6] McGill, Diane and Lavon Williams, “Psychological dynamics of sport and exercise” (3rd ed.). Champaign, IL: Human Kinetics. (2008): 177-178