What Does Fatigue Mean? Here’s What You Need To Know

Last updated: January 26th, 2021

If you regularly feel tired, you’re not alone. Sources indicate that up to 45% of individuals in various populations, including healthy and diseased individuals of all ages, report experiencing fatigue. (6)(11)(12)(23)

In this article, we’ll define fatigue and explain how you can improve low energy levels with our ten tips to address fatigue.

What is fatigue?

According to the World Health Organization’s International Classification of Diseases (ICD), fatigue is a general symptom that involves a feeling of lethargy, exhaustion, or low energy. Fatigue is typically experienced as depleted mental or physical resources, decreased work capacity, and a reduced response to stimuli (e.g., a reduced response time). Fatigue occurs following physical or mental exertion, which is considered normal, although it may also occur without exertion as a symptom of certain health conditions. (39)

Acute fatigue

Acute or short-term fatigue is temporary tiredness, such as fatigue during or after exercise and fatigue following lack of sleep. Approximately 5% to 45% of healthy individuals report occasionally feeling acute fatigue. (12)

Chronic fatigue

Chronic fatigue is long-term fatigue characterized by experiencing tiredness for a period of six months. (25) Approximately 2% to 11% of individuals in the general population experience chronic fatigue. (12)

Chronic fatigue syndrome

Myalgic encephalomyelitis, commonly referred to as chronic fatigue syndrome (CFS), is a condition characterized by extreme fatigue lasting six months or more. CFS also involves experiencing at least four of eight chronic fatigue syndrome symptoms. Currently, there are no tests that can be used to identify CFS, and chronic fatigue syndrome is diagnosed by differential diagnosis, which means that other health conditions and causes of fatigue must be ruled out before a CFS diagnosis is made. (40)

Fatigue causes

Fatigue causes and risk factors, which have been associated with general fatigue and/or chronic fatigue syndrome, include:

• Alcohol consumption (14)
• Being female (women have an increased risk of chronic fatigue syndrome)
• Certain medications (e.g., analgesics, sedatives) (15)
• Certain nutrient deficiencies (e.g., B vitamins, (18) magnesium) (32)
• Dysbiosis (i.e., imbalance of microbiota in the gut) (29)
• Sleep loss (16)

Fatigue can also occur as a symptom of many health conditions, such as:

• Anemia due to various causes (38)
• Cancer (3)(15)
• Conditions caused by certain infections (e.g., Lyme disease, mononucleosis) (15)
• Depression (8)
• Diabetes (types 1 and 2) (13)
• Fibromyalgia (5)
• Hypothyroidism (1)
• Inflammatory conditions (e.g., inflammatory bowel disease, (30) multiple sclerosis, (36) rheumatoid arthritis) (24)
• Insomnia (2)

Research suggests that irregularities in certain processes may contribute to fatigue, such as impaired inflammation, autonomic nervous system dysfunction, immune system activation, and hypothalamic-pituitary-adrenal (HPA) axis dysfunction. (15)(25)

Did you know? Adrenal fatigue is a term commonly used to describe fatigue and related symptoms. Adrenal fatigue is said to result from the impact of chronic stress on the adrenal glands as these glands produce a variety of hormones involved in regulating your stress response, metabolism, and other functions. However, the existence of adrenal fatigue is disputed, and it is not officially recognized as a medical condition or disease. (35)

Fatigue symptoms

Fatigue symptoms include both physical and cognitive symptoms, such as:

• A decline in accuracy, speed, and power in physical performance
• A decline in physical capacity following exercise
• Decreased cognitive function (e.g., accuracy completing tasks, reaction time) (12)
• Lethargy (a lack of enthusiasm) (39)

Ten tips to improve fatigue and boost energy levels, naturally

Fatigue treatment should be personalized to the individual and may include treating health conditions that are causing fatigue. (12) The following tips can help you improve your low energy levels by addressing some of the causes of fatigue.

1. Choose anti-inflammatory foods

A review study that examined the effects of anti-inflammatory nutrients, foods, and dietary patterns on fatigue and inflammatory markers found that an anti-inflammatory diet including polyphenol-rich vegetables, whole grains high in fiber, and omega-3 fatty acids was associated with improvement in disease-related fatigue symptoms. (17)

For information on the best foods to boost your energy levels, visit the Fullscript blog.

2. Stabilize your blood sugar

Research suggests that fluctuations in blood glucose (sugar) levels, such as the alterations in blood glucose levels seen in diabetes, can contribute to fatigue. (13) One simple approach to help stabilize your blood sugar and energy levels begins with reducing your carbohydrate intake at breakfast. One study observed the effects of breakfasts with varying amounts of carbohydrates (15 g to 50 g) and fiber (1.5 g to 13 g) on cognition and mood. The results suggest that consuming a breakfast high in carbohydrates is associated with feelings of tiredness. (28)

Did you know? Certain intermittent fasting regimens have been associated with improved blood glucose levels and reduced mental fatigue. (41)

3. Minimize your caffeine intake

Caffeine, a nervous system stimulant, is commonly used to increase alertness and fight fatigue. However, caffeine intake has been associated with irregular levels of melatonin at night, the hormone that induces sleep, (31) resulting in impaired sleep and daytime sleepiness. (22) A controlled trial comparing the effects of 400 mg of caffeine at various times before bedtime. Based on the findings, the researchers recommend avoiding caffeine intake at least six hours before your bedtime and warn that higher doses, even earlier in the day, may interfere with sleep. (10)

Keep in mind that caffeine is found in various beverages and foods, including:

• Chocolate
• Coffee
• Energy drinks
• Non-herbal teas (e.g., black, green)
• Soda (31)

Did you know? Approximately 90% of U.S. adults consume caffeine-containing beverages daily. (31)

4. Don’t wind down with alcohol

Similarly to caffeine, alcohol intake has been found to negatively affect sleep quality and quantity, resulting in increased fatigue. While alcohol is known as a sedative and used as a sleep aid, it can also increase wakefulness in the second half of the night. (14) Further, hangover from alcohol consumption is associated with increased fatigue and anxiety, as well as decreased alertness the following day. (4) Consider replacing your nightcap with non-alcoholic beverages, such as herbal tea, and seek support for alcohol cessation if required.

5. Drink more water

Increasing your water intake can help improve low energy levels, particularly if you’re dehydrated. One trial found that when individuals who regularly consumed about 34 ounces (1 L) of water per day increased their water intake to 85 ounces (2.5 L), they experienced a significant decrease in fatigue, confusion, and thirst. (33) Water intake requirements will vary based on your age, sex, body size, level of activity, and climate. In general, the Food and Nutrition Board recommends women consume 91 oz (2.7 L) and men consume 125 oz. (3.7 L) of water daily. (20)

Did you know? You can easily add flavor to your water by squeezing in some citrus or adding in fresh herbs, such as mint and ginger!

6. Get active

When you’re fatigued, you may feel like the last thing you want to do is exercise, but research suggests that aerobic exercise has beneficial effects on energy levels. One controlled trial that assessed the effects of a six-week intervention of low- and moderate-intensity aerobic exercise in sedentary adults with fatigue found that low-intensity exercise had greater benefits. (34) You can gradually introduce exercise into your routine by starting with low-intensity activities, such as walking, swimming, and cycling.

7. Work within your personal limits

The Centers for Disease Control and Prevention (CDC) recommends that individuals with chronic fatigue syndrome identify and respect their personal limits for physical and mental activity, sometimes referred to as staying within your “energy envelope”. Finding a personal balance will require some trial and error as each individual will have different limitations for everyday activities, exercise, work or education, and social engagement. Personal limitations may be based on the level of fatigue and severity of other symptoms, such as cognitive dysfunction. (7) The “energy envelope” approach may also be useful to individuals with general fatigue.

8. Find out if you’re a ‘morning’ or ‘night’ person

Are you a “lark” or a “night owl”? Researchers have identified different chronotypes, which refer to individual differences in sleep/wake patterns. You may find that your energy levels, mental alertness, and performance peak at a certain time of day corresponding to your chronotype, and this can be considered this when planning your day. (19)(26)

The different chronotypes include:

• Definitely morning type
• Moderately morning type
• Neither type
• Moderately evening type
• Definitely evening type (19)(27)

9. Improve your sleep habits for better sleep

A variety of lifestyle behaviors, referred to as sleep hygiene habits, can help you get a better night’s sleep and feel more rested. In addition to limiting your caffeine and alcohol intake, sleep hygiene recommendations include reducing light and noise in your sleep environment and maintaining a regular sleep schedule. (21)

Download a handout on 7 lifestyle tips for better sleep.

10. Practice mindfulness or other stress-reduction techniques

A study in individuals with chronic fatigue syndrome investigated the effects of a four-day mindfulness-based program, which consisted of counseling, stress management, mindfulness training, physical exercise, and mindfulness-based cognitive behavioral therapy (MBCT). Results showed that 80% of the individuals had significant improvements in the fatigue and physical functioning scales used to measure outcomes. (37) You can explore various activities with a mindfulness component, such as MBCT, meditation, yoga, and body scanning. (9)

Bonus: Speak with your practitioner about your fatigue

If you notice your fatigue persists, it’s important to speak to your integrative healthcare practitioner, who can help you to identify and address the underlying causes. Fatigue treatment may involve working with your practitioner to treat a nutrient deficiency or related health condition, such as the ones listed in this article.

The bottom line

If you regularly experience tiredness, take some time to check in with yourself and consider which fatigue causes may be a contributing factor. Try the tips in this article to help improve low energy levels. Lastly, if you struggle with chronic fatigue or experience sudden extreme fatigue, we recommend speaking to your integrative healthcare practitioner for further guidance.