Energy & Fatigue

Last Updated: August 16, 2022

Energy is the ability to do work. In humans, energy affects the ability to sustain physical and cognitive activity, and may also refer to the subjective experience of being able to do so. Fatigue is the opposite: a lack of energy, often as a result of exertion or disease.

What does energy and fatigue encompass?

Fatigue is generally defined as extreme tiredness due to exertion or illness, whereas energy refers to the actual or perceived ability to power physical and mental activity. Fatigue in exercise science is slightly different: fatigue is characterized as diminished output in response to sustained effort.[1] The broad topic of fatigue and energy is related to nutrient status, metabolism and energetics (i.e. mitochondria function), exercise, physiology, psychology, neurobiology, oxidative stress, inflammation, sleep, and many body systems. Fatigue can be as mild as feeling tired regularly, or as extreme as the disabling fatigue indicative of a severe medical condition (i.e. chronic fatigue syndrome (CFS), also known as ME/CFS).[2]

How could diet affect energy and fatigue?

Food choice is foundational for sustaining energy, as calories are metabolized into ATP, the primary source of energy that fuels cell needs. Healthy, nutrient dense dietary patterns support the energetic demands of life, prevent conditions that increase risk for fatigue, and have been used in studies to reduce fatigue and increase energy.[3][4] Some foods contain nutrients at doses shown to support energy and resist fatigue either in general (e.g., iron in red meat) or during exercise (e.g., nitrates in spinach).[5]

Which supplements are of most interest for energy and fatigue?

Getting enough essential vitamins and minerals (e.g., iron for blood cell function, B-complex vitamins for metabolism support) is foundational in any approach designed to address fatigue, which means that supplementation can be beneficial if the diet does not provide enough of these nutrients.

The most common supplements used for increasing mental and physical energy are stimulants (e.g., caffeine, guarana). Supplements that improve cognitive function, like nootropics, are also related to increasing energy.

Supplements that increase endurance, support fatigue resistance, promote stress tolerance, or have another effect on enhancing exercise (such as ergogenics) are relevant to energy and fatigue.

Don't miss out on the latest research

  1. ^Wan JJ, Qin Z, Wang PY, Sun Y, Liu XMuscle fatigue: general understanding and treatment.Exp Mol Med.(2017-10-06)
  2. ^Committee on the Diagnostic Criteria for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome, Board on the Health of Select Populations, Institute of MedicineBeyond Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Redefining an Illness
  3. ^Centers for Disease Control and PreventionPoor Nutrition(2022 May)
  4. ^Zick SM, Colacino J, Cornellier M, Khabir T, Surnow K, Djuric ZFatigue reduction diet in breast cancer survivors: a pilot randomized clinical trial.Breast Cancer Res Treat.(2017-01)
  5. ^Jonvik KL, Nyakayiru J, Pinckaers PJ, Senden JM, van Loon LJ, Verdijk LBNitrate-Rich Vegetables Increase Plasma Nitrate and Nitrite Concentrations and Lower Blood Pressure in Healthy Adults.J Nutr.(2016-05)
  6. ^The content of this page was partially adapted from MedlinePlus of the National Library of Medicine
  7. ^Campbell B, Wilborn C, La Bounty P, Taylor L, Nelson MT, Greenwood M, Ziegenfuss TN, Lopez HL, Hoffman JR, Stout JR, Schmitz S, Collins R, Kalman DS, Antonio J, Kreider RBInternational Society of Sports Nutrition position stand: energy drinksJ Int Soc Sports Nutr.(2013 Jan 3)
  8. ^Li-Ng M, Kennedy LAdrenal InsufficiencyJ Surg Oncol.(2012 Jul 17)
  9. ^Salvatori RAdrenal insufficiencyJAMA.(2005 Nov 16)