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Exercise & Cortisol: balancing the benefits & risk of intentional stress

An insidious pandemic has brought a new dimension of fear and uncertainty into our already stressful lives. As case numbers soar, so do reports of stress, anxiety and depression.

Gym closures and lockdowns are forcing many to curb their level of movement, while others, feeling oppressed by the indoors, are doubling down on socially distanced outdoor activities to regain a sense of control and burn off stress.

Physical activity and stress have a complex relationship. It is well known that physical activity promotes physiological adaptations which support long term health. Regular exercise strengthens our muscular and cardiovascular systems while simultaneously toning our nervous system, impacting both physical and mental well-being. But there is a caveat: a high existing stress load makes us more susceptible to the potentially harmful effects of intense exercise. We must be weary when working with highly stressed, high-performing athletes not to push them too far.

The Cumulative Stress Load: The Good, The Bad and Everything in Between

Stress is defined as any reaction to a physical, mental or emotional stimulus that challenges the body’s state of homeostasis or balance. This could be something generally perceived as positive like the excitement of a first date or a rush of energy before a race, or negative like the fear of an imminent public speaking engagement or a serious injury or illness. The body cannot perceive whether a stimulus is good or bad nor can it distinguish a critical event from a minor disturbance.

In all of these cases, the hypothalamus-pituitary-adrenal (HPA) axis is activated, triggering cortisol to rush the system and facilitate a speedy reaction. Cortisol is a non-discriminating energy and performance enhancing steroid hormone that induces a profound response throughout the body. Among its many effects, it increases blood flow and oxygen to the brain and muscles so we can run and think faster while releasing fats and carbohydrates so we have access to stored fuel. Cortisol is secreted from the adrenal glands in sync with our circadian rhythm, peaking to provide energy in the morning and slowly declining over the day to allow us to fall asleep at night.

When we face situations of acute stress, cortisol spikes and effects are magnified. This can be useful before a workout or competition when a quick kick of cortisol gives us the rush that helps us perform. Once the perceived stress stimulus dissipates, cortisol falls and we are able to return to a relaxed parasympathetic state in which the body can attend to long-term, non-critical functions like recovery and digestion. However, in today’s world, cortisol levels climb higher with each announcement of new cases, work email, fight with partner, reality TV show, intense workout and notification on our phone. As these stressors build up over the course of the day, so does the cumulative cortisol load.

Constantly elevated stress hormones can be problematic, so we as health care providers and coaches must be weary of adding more stress onto someone who is already managing a heavy load. It is important to remember that each client will handle a stressful situation differently. Two clients might both be experiencing the same stressful event – a breakup, for example – and yet their perceived level of stress may be completely different. It is this perceived level of stress that is important here. If a person believes a breakup is the end of the world, their body does too.

Excessive long-term stress can lead to dysregulation of our cortisol management system, the HPA axis. This can result in chronic cortisol exposure which limits less critical long-term projects like digestion (learn more here) and immune health. Cortisol is catabolic: it breaks down both lean body mass and muscle mass to make quick energy available to us. Meanwhile, it increases appetite and fat mass, encouraging dangerous fat deposits to accumulate around the midsection. It has been shown to increase inflammatory interleukin-6 (IL-6) which has been associated with a range of disorders including Alzheimer’s, osteoporosis and cancer. IL-6 contributes to diabetes and cardiovascular disease further exacerbated by high levels of blood cholesterol, triglycerides, blood sugar and blood pressure also caused by excessive cortisol levels.

Eustress: How Regular Exercise Helps Fight Stress

Exercise is a particularly interesting stressor because, if implemented correctly, it can tone the nervous system, leading to lower resting cortisol levels, a faster return to the parasympathetic state and a higher threshold for dealing with stressful situations. Beneficial stressors of this nature are called eustress. Physical fitness and the eustress of regular physical activity have been linked to improved mental health including reduced symptoms of depression and anxiety: especially relevant in today’s uncertain world in which mental health concerns are sky-rocketing.

Study after study has shown that anxiety symptoms decrease in response to moderate or high intensity exercise. Typically, aerobic exercise shows better results for mental health than strength training. In general, we see that perceived stress is inversely associated to one’s fitness level.

Overtraining Syndrome: When Training Contributes to Stress

The benefits of regular exercise are clear but it is possible to push someone too far. Overtraining Syndrome (OTS), also referred to as burnout, staleness, failure adaptation, under-recovery, training stress syndrome and chronic fatigue, is characterized by a decrease in performance accompanied by disorders of the nervous, endocrine and/or immune systems. Psychological imbalances such as anxiety and depression are commonly observed with OTS.

OTS typically arises when increased training duration and/or intensity is not balanced with sufficient recovery. If the body is dealing with an additional stressor (such as an ever-evolving pandemic, a bout of cold weather, an illness, a divorce or a poor diet), the cumulative stress load becomes even higher and more difficult to offset with recovery strategies.

Full-blown OTS can take years to recover from. Catching a client in the early stages is key to turning the situation around quickly. Warning signs include:

- Decreased performance

- Fatigue

- Hunger

- Excessive muscle soreness

- Increased susceptibility to colds and flus

- Your client may express feeling stressed

- They might admit they are struggling to get enough sleep

These are signs to reduce the frequency or intensity of the training regimen and focus on recovery. Coach your client to identify and address the stressor. If symptoms progress to increased fatigue, pain, depression, anxiety or cravings for sweets it may be an indication of further deterioration. It is important to stop all high-intensity training as these symptoms may be accompanied with serious consequences such as menstrual disturbances, hormone imbalance including chronically elevated cortisol, increased resting and exercise heart rate, and increased frequency of illness and injury. At this point, full recovery may take months or years.

If your client is working through a stressful period, be mindful of the duration and intensity of the activities you include in their plan. Keep in mind that endurance athletes, subject to long and intense training sessions, tend to be more at risk of OTS. Be sure to include sufficient rest days and suggestions for recovery.

Strategies to promote recovery for at risk clients might include:

  • Diet: Coach clients to avoid processed foods including sugar, caffeine and alcohol. An anti-inflammatory whole foods diet with adequate complex carbohydrates and lean proteins is a good starting point for athletes. Learn more about diet basics in our course, Foundational Nutrition: Principles for Optimal Health.

  • Rest: Athletes should aim for 8-10 hours of sleep each night. Note that cortisol spikes from exercising too late in the day may affect sleep patterns. Rest days should be included in any fitness plan and clients should be encouraged to listen to their bodies and take more time to recover from workouts when necessary. People with a menstrual cycle may perform better on a training regimen that takes into account their monthly hormone fluctuations. Incorporating rest days on days 1-3 of their cycles may prove beneficial to some. We have a course coming soon that deep dives into this topic. Sign up for our mailing list to be the first to get the details!

  • Mental/emotional: Support your clients in making a conscious effort to engage the parasympathetic state. Try ending sessions with a slow, deep stretch and a few mindful breaths. Meditation and deep breathing practices have been shown to reduce the perception of stress and improve symptoms associated with depression and anxiety. Check out Jenna’s suggestions for engaging the parasympathetic nervous system here.

Physical activity is an accessible tool that almost anyone can use to maintain physical and mental wellness when practiced in a sustainable way. In these strange and stressful times, it is especially important that we meet our clients where they’re at and give them the tools they need to support adequate recovery in between training sessions. Balancing exercise and other stressors with recovery is the key to improved performance, effective weight loss and optimal health.

Camila Montaner is a Certified Nutritional Practitioner dedicated to supporting those in search of balance in a demanding world. Camila’s background in communications launched her into a busy career before she had developed tools to manage the pressure. Decades of stress and anxiety led her to the world of holistic nutrition where she learned, through much trial and error, how to develop a more grounding routine. Today, she uses her communications background to bring the wellness techniques she learned to others struggling to find their own equilibrium. Her approach to wellness harnesses the power of plants and accessible lifestyle strategies to restore energy, mood and wellbeing.

In the rare moment she’s not cooking, eating or writing about food, you’ll find Camila getting lost in the woods, the waves or the pages of a good book.

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