Stress, Adaptation, and Performance

Stress, Adaptation, and Performance

Dr Brad McEwen PhD, MHSc (Hum Nutr), BHSc

Naturopath | Nutritionist | Herbalist | Educator | Researcher | Mentor

Optimum nutrition and herbal medicines play fundamental roles in optimising health reducing stress, and improving performance. There is a greater need for performance and recovery in sports and everyday life. Something to note is that performance and recovery is not just physical, but holistically a combination of physical, mental, and emotional health and performance. Those who exercise suffer from less depression, anxiety, fatigue, and cognitive impairments (reference). Stress is experienced every day. This article explores some vital nutrients and herbs that have shown benefit in reducing physical, mental and/or emotional stress.

Stress can be defined as a state of threatened homeostasis or balance within the body (reference). Stress events can accumulate and build up over time and greatly impact health (reference). A “stressor” is any stimulus or event that evokes a physiologic stress response (reference). Anything that causes stress endangers life, unless it is met by adequate adaptive responses. On the other hand, anything that endangers life causes stress and adaptive responses. Adaptability and resistance to stress are fundamental conditions for life, and every vital organ and function of the body participates in them (reference).


Stress is counteracted by adaptive processes involving affective, physiological, biochemical, and cognitive-behavioural responses. This is an attempt to regain homeostasis and balance in the body. Stress reactions are always followed by recovery processes, which may be compromised when stressors are severe, prolonged, or unaccustomed to the person. The adaptive capacity to deal with stress is the fitness level of a person (reference).

Humans function on a continuum between sympathetic (fight or flight) and parasympathetic (rest and digest) (reference).


General Adaptation Syndrome was described in 1946 by Hans Selye (reference). It develops in three stages: the Alarm Reaction, the Stage of Resistance, and the Stage of Exhaustion (reference).

It is noted that most of the characteristic manifestations of the alarm reaction stage, such as tissue catabolism, hypoglycaemia, gastrointestinal erosions, discharge of secretory granules from the adrenal cortex, haemoconcentration, etc., disappear or are actually reversed during the stage of resistance, but reappear in the stage of exhaustion (reference).

Dietary measures are of particular importance in influencing the course of the general adaptation syndrome (reference).

Cortisol is a vital catabolic hormone produced by the cortex of the adrenal gland. It is released in a diurnal fashion, with blood levels peaking in the morning to facilitate arousal and steadily declining thereafter (reference).

Throughout the day, cortisol maintains and regulates blood glucose to provide energy to an actively functioning brain and neuromuscular system (reference).

Cortisol is also a potent anti-inflammatory hormone. It prevents the widespread tissue and nerve damage associated with inflammation (reference).

A stress-induced increase in cortisol secretion is adaptive in the short-term. Excessive or prolonged cortisol secretion may have negative effects on the body, both physically and psychologically (reference).


Pyridoxine (Vitamin B6) is a water-soluble vitamin that plays a major role in health. It has numerous functions, including:

  • Involved in over 100 different enzymes (reference)
  • Central role in the metabolism of amino acids (reference) and protein (reference)
  • Metabolic processes of lipids and carbohydrates (reference)
  • Antioxidant effects via glutathione peroxidase pathway (reference)
  • Metabolism of homocysteine to cysteine (reference)
  • Involved in trans-sulphuration and transmethylation (reference)
  • Biosynthesis of numerous neurotransmitters, such as dopamine, adrenaline, noradrenaline, gamma-aminobutyric acid, histamine, and serotonin (reference)

Closely associated with the functions of the nervous, immune and endocrine systems (reference)

Magnesium is a mineral that is essential for most living cells (reference) and is involved in over 600 enzymatic reactions (reference). Magnesium plays an important physiological role particularly in the brain, heart, and skeletal muscles (reference). It is a cofactor for DNA and RNA, and for the storage, transfer, and utilisation of ATP (reference). Magnesium is involved in improving mitochondrial health, the maintenance of normal muscle and nerve function, neurotransmitters, bone strength, heart rhythm, and the immune system (reference).

Magnesium supplementation has been positively associated with improved physical performance and magnesium intake has been associated with improved physical performance in older adults (reference).

Magnesium can be beneficial for headaches and migraines as serum levels have been found to be lower in migraine sufferers. Magnesium improves mitochondrial health, neurotransmission, nitric oxide metabolism, and metabolism of neurotransmitters (reference).

A deficiency of magnesium can lead to neuromuscular excitability, spasms, cramping, numbness and tingling, and nervousness (reference). Low magnesium intake and/or status has been associated with critical health issues, such as but not limited to hypertension, cardiovascular disease, type 2 diabetes, and osteoporosis (reference). A deficiency of magnesium has been associated with inflammation in chronic disease (reference).

An 8-year study in elite international Olympic and Paralympic track and field athletes found that athletes with a history of achilles or patella tendon pain had significantly lower magnesium levels than average (reference).

Zinc is an essential mineral for all forms of life. Zinc has catalytic, structural, and signalling functions. Having enough zinc positively affects many cellular processes (reference). Zinc binds to over 2,500 proteins, equivalent to 10% of total human proteome. It maintains the structural integrity for many of the proteins (think zinc-finger proteins) (reference). It is involved in the stabilisation of proteins and structure, transcription factors, redox signalling, and in DNA repair (reference). It is involved in insulin sensitivity and glucose metabolism (reference). Zinc is able to interact with sulphur groups in proteins (reference). It is involved with the major antioxidant complex copper/zinc superoxide dismutase and increases glutathione activity (reference).

For skeletal muscle health, zinc has been found to affect the formation of muscles and muscle regeneration due to its effects on muscle cell activation, proliferation, and differentiation (reference).

Zinc deficiency could be a crucial issue in sport performance for athletes (reference). Zinc levels fluctuate during exercise due to requirements (energetics, antioxidant, etc). Studies on the effect of exercise on zinc status found decreased serum zinc for aerobic exercise, aerobic endurance and muscular strength, acute physical activity, 30-40 minutes of cycling, 9.6 km run, 90% of VO2Max, and prolonged road-running (reference).

Zinc deficiency leads to generalised poor growth, skeletal muscle issues, loss of appetite, immune abnormalities, mental lethargy, cardiovascular disease, anaemia, inflammation, oxidative stress, lipid peroxidation, and rough skin (reference).

Ashwagandha (Withania somnifera) has long been used in the traditional Ayurvedic medicine to enhance memory and improve cognition (reference). Ashwagandha is known as the “rejuvenator” and “revitaliser” (reference).

Some of the functions and uses of Ashwagandha:

Improved quality of life in healthy athletic adults (reference)


Brahmi (Bacopa monniera) has been used for centuries in Ayurvedic medicine, either alone or in combination with other herbs, as an enhancer of cognitive performance (reference) and as a memory and learning enhancer (reference). Brahmi is used in Ayurveda as a nootropic to improve intellect and memory. It is an important component of many Ayurvedic herbal formulations that target the central nervous system and to manage conditions such as memory, lack of concentration, and anxiety (reference).

Some of the functions and uses of Brahmi:


A randomised double-blind placebo-controlled trial found that Brahmi significantly improved speed of visual information processing, learning rate, and memory consolidation (reference).

A meta-analysis suggested that Brahmi has the potential to improve cognition, particularly speed of attention (reference).


Green tea (Camellia sinensis) has been used as a beverage for millennia and has numerous health benefits. 

Some of the functions and uses of Green tea:

Lemon Balm (Melissa officinalis) is a medicinal plant that has long been used in European and other Traditional Medicines, particularly for its memory-enhancing properties.

Some of the functions and uses of Lemon Balm:


Contains Rosmarinic acid which has positive effects on mood and cognitive function (reference). 

A study investigated the effect of single doses of 600 mg, 1000 mg, and 1600 mg of Lemon Balm, or a matching placebo, in healthy young participants, at 7-day intervals. Cognitive performance and mood were assessed pre-dose and at 1 hour, 3 hours, and 6 hours post-dose. Improved memory performance, mood, and increased “calmness” (reference).

Lemon Verbena (Aloysia citrodora) is a species of flowering plant in the verbena family Verbenaceae, traditionally used for its effects on digestive disorders and rheumatism (reference).

Some of the functions and uses of Lemon Verbena:

Optimum nutrition and herbal medicines play fundamental roles in optimising health and performance, particularly for stress.


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