Overtraining: How Stress Impacts Our Hormones
Weight training, fasting, cardio, cutting calories, food restrictions, skipping meals …The only way to progress with our fitness goals is to do more, right? Extreme dieting is becoming more and more prevalent with the rising popularity of fitness/ bodybuilding competitions and online ‘fitspo’ personalities. Although health and fitness goals are fantastic, where is the line and how much is too much – how does overtraining affect us?
Overtraining occurs when the volume and intensity of exercise exceeds an individual’s capacity to recover. Although this term is largely linked to performance and the physical aspects of training, overtraining is also a significant problem on a physiological level. When our body is under high stress for prolonged periods of time, a cascade of issues begin to occur leading to conditions such as inappropriate permeability of the gut, decreased immunity (so more infections), hypothyroidism, hormonal dysregulation (low testosterone in men, dysregulation and low oestrogen and progesterone in women) with a possible loss in menstrual cycle in women (amenorrhoea).
So, what happens in our body for this to occur?
What is stress?
Stress is an imbalance between our demands and the resources we have in which to cope with these demands. Stress is often seen as a psychological response (that stress we can FEEL), but also includes the physical and metabolic demands in which the body works harder than it normally would. Physical stress can include a heightened physical demand on the body while metabolic stress can include malnutrition and under-eating (i.e. a calorie deficit).
When under stress, our body switches into a sympathetic ‘fight or flight’ response. The release of stress hormones cortisol, adrenaline and inflammatory cytokines are used to prime our body for extreme life-threatening situations, such as running away from a bear. Unfortunately (or fortunately!) in this modern day, the stress we experience is very different from our ancestors and does not always require this same response. Our body is always trying its best to keep us safe, it just can’t determine whether we’re starving and being chased by bears or dieting and running on the treadmill to reach our fitness goals!
Some stress is normal and exercising/ dieting CAN be done in a perfectly healthy way. Some controlled degree of stress is actually essential for improved performance via adaption. Issues only arise when prolonged exercise and dieting regimes become too intense for our body to cope with. When these extremes occur, the body must and does, begin to prioritise.
We also consider mental stress so important we created a whole course (Mind Power: eCourse & Face to Face) to manage or give you the best techniques to handle life and the normal stresses it contains.
Stress and Its Effects on Our Brain
The body’s main goal is to keep us alive which, in some circumstances, may mean choosing between different bodily processes to keep us functioning. When our body is under extreme stress, it places vital bodily processes as a priority while pushing reproduction to the back-burner. From our body’s internal perspective, our environment is too dangerous to grow and raise children, so it instead focuses its limited resources on keeping us alive to maybe reproduce another day.
Parts of our brain called the hypothalamus and pituitary gland are stimulated by our bodies stress response through the hypothalamic-pituitary-adrenal-gonadal (HPAG) axis. Over time, these parts of our brain become overwhelmed by this chronic stress and begin to down-regulate (slow down) – they’re in desperate need of a break! The hypothalamus is a part of the brain located just above the brainstem, with the primary function to maintain homeostasis (stability/ balance) within the body. The pituitary gland, which is attached to the hypothalamus, is a pea-sized structure which either produces directly or stores hormones from the hypothalamus and releases them into the blood stream when appropriate. Hormones which these structures mediate include:
- Human-growth hormone (GH)
- Thyroid stimulating hormone (TSH)
- Follicle-stimulating hormone (FSH)
- Luteinizing hormone (LH)
- Prolactin (PRL)
- Andrenocorticotropic hormone (ACTH)
- Melanocyte-stimulating hormone (MSH)
- Oxytocin (OT)
- Antidiuretic hormone (ADH)
- Corticotrophin-releasing hormone and andrenocorticotropic hormone (ACTH) which stimulate the release of cortisol from the adrenal cortex
What’s Happened To My Cycle!
As the hypothalamus and pituitary gland begin to slow down their release of these hormones, there is a ripple effect throughout the body in the areas in which these hormones work. LH and FSH travel from the pituitary gland to the ovaries and testicles via the blood stream to stimulate the release of other reproductive hormones such as estrogen, progesterone and testosterone. If these hormones are not stimulated by the pituitary hormones, then our gonadal (reproductive) axis begins to struggle. In females, this can cause irregular menstruation, amenorrhoea (the loss of menstruation) and a variety of related symptoms such as acne, low libido, mood issues and hirsutism (abnormal hair growth). In males this may also cause hormonal dysregulation, including low testosterone, which may lead to a lack of libido, mood issues, decreased sexual function, fatigue, muscle weakness and gynecomastia (development of breast tissue).
The thyroid is a gland in the neck which regulates the body’s metabolic processes such as our heart rate, body temperature and weight. Thyroid Stimulating Hormone (TSH) is released by the pituitary gland and does as its name suggest: stimulates the thyroid to function correctly. If levels of TSH are inadequate, thyroid hormones such as T4 are not appropriately released and able to synthesis T3, the thyroid’s more ‘active’ hormone. Stress also impacts the conversion of T4 to T3 due to higher levels of cortisol induced reverse T3. rT3 is a mirror image of the normal T3 hormone and it replaces T3 on receptor sites and does not let the active T3 do its job. Inflammatory cytokine TNF-alpha, released during the stress response, also decreases the sensitivity of the thyroid gland to TSH. Stress effects the thyroid in a multitude of different ways!
Symptoms of hypothyroidism may include:
- Increased sensitivity to the cold
- Dry skin
- Weight gain
- Muscle weakness
- Impaired memory
Tips to Avoid Overtraining
The point at which symptoms of overtraining becomes a problem largely depends on a range of factors such as other stressors, gut health, inflammation, predisposition to hormonal/ thyroid problems and the individuals state of health prior to overtraining.
The best way to avoid overtraining is by working off a risk to benefit ratio, having realistic goals, setting appropriate time restraints and only doing what is truly necessary at any one time – more is not always better or more effective! A slow and sustainable approach to our fitness goals is not only healthier, but more sustainable in the long-term. When undertaking a period of dieting or high physical activity, it is important to be guided by a qualified practitioner. Learn more about the foundations for athletic performance – clinical coaching .