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Energy and Fatigue: Their Differences & How Coaches Can Address Them

“Persistent fatigue is a common problem (∼20-45% of U.S. population), with higher prevalence and severity in people with medical conditions.” In a research paper by Loy, Cameron, and O’Connor published by the US Department of Health and Human Services (2019), researchers hypothesized that energy and fatigue are different and unique experiences. They find that energy and fatigue are two unipolar states of being—similar to light vs. dark and potent smell vs. no smell—that should not be measured on the same scale. Below we examine the research of Loy, Cameron, and O’Connor and how executive coaches can apply this new perspective on energy vs. fatigue in their coaching practice today.

“The energy of the mind is the essence of life.” - Aristotle

The importance of understanding energy vs. fatigue

Understanding the differences between energy and fatigue is important because of the influence that both qualities have on productivity. Consider the following research:

  • The National Safety Council indicates that fatigue (related to lack of sleep) costs “employers about $136 billion a year in health-related lost productivity” alone (2017).

  • Research from Peng et al. (2021) indicates that fatigue is a “significant mediator of mental health” and that interventions designed to decrease “fatigue would reduce mental health problems among healthcare workers during the COVID-19 pandemic” (Peng et al., 2021).

  • Research indicates that fatigue has a “strong association” with “reduced cognition,” “occupational accidents,” and “some forms of cancer.” Fatigue also has negative effects on metabolism and reproductive health (Lock et al., 2018).

  • From the Texas Department of Insurance: “Fatigue has been cited as a factor in some of the biggest workplace accidents in history, including the 2005 BP Texas City oil refinery explosion and the 2010 Deepwater Horizon oil spill.”

  • Fatigue influences our decision-making processes. Research from the Journal of Health Economics indicates changes in energy levels or “decision fatigue” faced by surgeons at the end of their shift appeared to influence their care plan for patients (Persson et al., 2019).

Hypothesis: fatigue and energy are not opposite; they are different

According to Loy et al. “energy and fatigue are distinct perceptual states” and they “should be measured using separate unipolar scales” that acknowledge the “different mechanisms” behind both phenomena. Consider the chart below that outlines some of the differences between energy and fatigue shared by Loy et al.



“Increased by elevated dopamine”

“Increased by elevated brain serotonin”

“Increased by elevated… norepinephrine transmission and binding”

“Increased by elevated… inflammatory cytokines”

“More strongly impacted” by medical conditions than fatigue

“Increased by… reduced histamine binding”

“Likely evolved as part of a system that expedited approach-oriented adaptive behaviors” such as “hunting and gathering”

“Likely evolved” to promote “avoidance-oriented behavioral functions such as promoting rest”

“Sedentary behaviors have a stronger tendency to decrease energy”

“Affected by environmental changes independently of energy”

Evidence supporting the difference between energy and fatigue

Below we examine a variety of research findings that indicate a unique difference between energy and fatigue. First, we examine scenarios where energy is more greatly affected than fatigue. Secondly, we examine scenarios where fatigue is more affected than energy.

“Energy and persistence conquer all things.”- Benjamin Franklin

Scenarios where energy is affected differently than fatigue

  • “Sedentary behaviors (e.g., sitting at desks, watching television) have a stronger tendency to decrease energy than increase fatigue.”

    • “‘Acute exercise’ has a greater effect on energy levels than fatigue.” (Loy et al., 2013)

  • Energy after exercise is influenced by genetic factors more than fatigue.

    • A twin study by Schutte et al. (2017) has shown that “energy changes in response to moderate exercise were influenced by genetic factors, but fatigue changes were not.”

  • “Energy also is more strongly impacted than fatigue in a number of medical conditions and diseases.”

    • Research studying those with HIV shows that “lack of energy interferes with daytime function and is not just the inverse of fatigue but a distinct perception that differs from fatigue” (Aouizerat et al., 2013).

  • Dopamine levels in the brain and caffeine consumption have been shown to “influence energy” levels, but not fatigue.

    • Research from Cameron & McMillian indicates that methylphenidate (a drug that influences dopamine levels in the brain) does not reduce fatigue in individuals with multiple sclerosis (2017).

“A man grows most tired while standing still.” - Chinese Proverb

Scenarios where fatigue is affected differently than energy

  • Psychological interventions are shown to have a greater effect on fatigue than energy levels.

    • In a meta-analysis of “psychological and activity-based interventions for cancer-related fatigue” it was found that “among the psychological studies, there was evidence that intervention was more likely to decrease fatigue than increase vigor” (Jacobsen et al., 2007).

  • Fatigue “affected by environmental changes independently of energy.”

    • Researchers Harris & Dawson-Hughes (1993) found that “there were significant changes over the year in scores for… Fatigue-Inertia” depending on the season (fall vs. summer).

    • Environmental changes that affect fatigue levels can also be non-environmental such as the color of paper as seen in research from Jacobs & Blandino (1992).

  • Specific foods and alcohols affect fatigue more than energy.

    • Research from Ashton et al., shows that “red wine” was “more fatiguing than white, with no difference in energy between wine types” (2017).

    • Research from Pasman et al. indicates that a breakfast of “complex carbohydrates” decreases fatigue more than a “simple carbohydrate” breakfast. However, there was no difference in energy levels (2003).

  • Serotonin levels in the brain “may be more strongly related to perceived fatigue than energy”

    • Serotonin levels also change in correlation (Lambert et al., 2002) with the seasonal changes referenced by Harris & Dawson-Hughes (1993) which has been linked to fatigue-levels.

  • “The neurotransmitter histamine may also influence fatigue more than energy.”

    • Research participants given “histidine, the amino acid precursor for histamine” reported reduced fatigue, but no changes in their energy levels (Sasahara et al., 2015).

  • Proinflammatory cytokines (that often occur in sickness) are related to increased levels of fatigue and unchanged levels of energy.

    • Research from Schedlowki et al. indicates that an increase in “proinflammatory cytokines” correlates with an “increase” in the levels of “fatigue” (2014).

“Our fatigue is often caused not by work, but by worry, frustration, and resentment” - Dale Carnegie

How executive coaches can respond

Based on the research above, we can conclude that energy and fatigue are different and unique states. With this information in hand, executive coaches can more effectively examine the energy levels and fatigue of their clients, with their clients. Knowing that there is a difference between energy and fatigue, executive coaches can more readily understand and examine the root cause of reduced productivity or goal achievement. In light of the research above, coaches can ask the following questions:

To examine energy levels

  • Do you take time to exercise and move in your workday?

  • How do you avoid a sedentary lifestyle?

  • How do you support your physical health and wellness?

  • Does your current health support your goals or hold you back?

To examine fatigue levels

  • How do you support your mental health and well-being?

  • Do you find that your level of fatigue changes with the seasons? If so, how?

  • How does your environment influence your fatigue levels? Do you find that you are less fatigued when spending time outdoors or in specific settings?

  • Does your diet reduce fatigue in your workday or do you feel it increases fatigue?

  • Are you experiencing any sickness or illness that is influencing your level of fatigue?

After identifying which state a client may need to address, coaches can then walk with their clients toward a new goal of reducing fatigue or increasing energy. The research above provides several indicators for how fatigue can be reduced and energy can be increased.

Strategies that increase energy levels

  • Avoid a sedentary lifestyle (prolonged periods of inactivity).

  • Engage in physical activity (walking, running, exercise, etc.).

  • Invest in overall health, specifically in terms of dopamine with the help of a medical professional as needed.

  • As an important part of physical health, ensure that you are getting adequate and appropriate levels of sleep.

Strategies that reduce fatigue levels

  • Consider mental health and well-being, and involve the help of a mental health professional as needed.

  • Examine stress levels and invest in ways to reduce stress in daily life.

  • With seasonal changes, such as a decrease in sunlight which increases levels of fatigue, invest more time outdoors during daylight hours.

  • Discuss how to create an environment that decreases levels of fatigue unique to the client.

  • Discuss dietary habits and how some foods such as complex carbohydrates can help reduce “fatigue” (Pasman et al., 2003). Enlist the help of a dietary professional as ?'needed.

  • Consider what physical health conditions might be contributing to an increase in levels of fatigue. Encourage the use of medical professional resources as needed.

The main takeaway

By understanding the unique differences between energy and fatigue, executive coaches can address setbacks and reductions in productivity and/or goal-setting with their clients. Discovering which state of being, fatigue or energy, needs to be addressed with clients through powerful questions can lead to the implementation of specific strategies that either increase energy or decrease fatigue with their clients—ultimately helping coaching clients achieve their goals.

“Leadership is not just about giving energy… it’s unleashing other people’s energy.” - Paul Polman


Aouizerat, B. E., Gay, C. L., Lerdal, A., Portillo, C. J., & Lee, K. A. (2013). Lack of Energy: An Important and Distinct Component of HIV-Related Fatigue and Daytime Function. Journal of Pain and Symptom Management, 45(2), 191–201.

Ashton, K., Bellis, M. A., Davies, A. R., Hughes, K., & Winstock, A. (2017). Do emotions related to alcohol consumption differ by alcohol type? An international cross-sectional survey of emotions associated with alcohol consumption and influence on drink choice in different settings. BMJ Open, 7(10), e016089.

Cameron, M. H., & McMillan, G. (2017). Methylphenidate is likely less effective than placebo for improving imbalance, walking, and fatigue in people with multiple sclerosis. Multiple Sclerosis Journal, 23(13), 1799–1801.

Harris, S., & Dawson-Hughes, B. (1993). Seasonal mood changes in 250 normal women. Psychiatry Research, 49(1), 77–87.

Jacobs, K. W., & Blandino, S. E. (1992). Effects of Color of Paper on Which the Profile of Mood States is Printed on the Psychological States it Measures. Perceptual and Motor Skills, 75(1), 267–271.

Jacobsen, P. B., Donovan, K. A., Vadaparampil, S. T., & Small, B. J. (2007). Systematic review and meta-analysis of psychological and activity-based interventions for cancer-related fatigue. Health Psychology, 26(6), 660–667.

Lambert, G., Reid, C., Kaye, D., Jennings, G., & Esler, M. (2002). Effect of sunlight and season on serotonin turnover in the brain. The Lancet, 360(9348), 1840–1842.

Lock, A. M., Bonetti, D. L., & Campbell, A. D. K. (2018). The psychological and physiological health effects of fatigue. Occupational Medicine, 68(8), 502–511.

Loy, B. D., & O’Connor, P. J. (2016a). The effect of histamine on changes in mental energy and fatigue after a single bout of exercise. Physiology &Amp; Behavior, 153, 7–18.

Loy, B. D., & O’Connor, P. J. (2016b). The effect of histamine on changes in mental energy and fatigue after a single bout of exercise. Physiology &Amp; Behavior, 153, 7–18.

Loy, B. D., O’Connor, P. J., & Dishman, R. K. (2013). The effect of a single bout of exercise on energy and fatigue states: a systematic review and meta-analysis. Fatigue: Biomedicine, Health &Amp; Behavior, 1(4), 223–242.

National Safety Council. (2016). Cost of Fatigue at Work.

Pasman, W. J., Blokdijk, V. M., Bertina, F. M., Hopman, W. P. M., & Hendriks, H. F. J. (2003). Effect of two breakfasts, different in carbohydrate composition, on hunger and satiety and mood in healthy men. International Journal of Obesity, 27(6), 663–668.

The Mediating Role of Fatigue Between Mental Health and Its Associated Factors: Evidence From Chinese Healthcare Workers During the COVID-19 Pandemic.

Persson, E., Barrafrem, K., Meunier, A., & Tinghög, G. (2019). The effect of decision fatigue on surgeons’ clinical decision making. Health Economics, 28(10), 1194–1203.

Sasahara, I., Fujimura, N., Nozawa, Y., Furuhata, Y., & Sato, H. (2015). The effect of histidine on mental fatigue and cognitive performance in subjects with high fatigue and sleep disruption scores. Physiology &Amp; Behavior, 147, 238–244.

Schedlowski, M., Engler, H., & Grigoleit, J. S. (2014). Endotoxin-induced experimental systemic inflammation in humans: A model to disentangle immune-to-brain communication. Brain, Behavior, and Immunity, 35, 1–8.

Schutte, N. M., Nederend, I., Hudziak, J. J., Bartels, M., & de Geus, E. J. (2017). Heritability of the affective response to exercise and its correlation to exercise behavior. Psychology of Sport and Exercise, 31, 139–148.

Texas Department of Insurance. (2020). The dangers of fatigue in the workplace.,accidents%20and%20injuries%20each%20year.

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