We all go through ups and downs, and it’s normal to feel tired sometimes. Fatigue is a term used to describe an overall feeling of tiredness, lack of energy, and motivation. To improve fatigue, you need to get to the bottom of what’s causing it. It may be caused by some minor factors like insufficient sleep or coming down with a cold. However, it can also be a symptom of some medical conditions, some of which can be debilitating or even life-threatening.
Our wellbeing largely depends on the surrounding circumstances. Our nutrition, sleep, and physical activity all contribute to our energy levels throughout the day. If you feel excessively tired, reevaluate your lifestyle and improve it by making simple changes.
Improving your sleep hygiene can significantly impact the way you feel. Getting enough sleep is essential for overall health. Insufficient or low-quality sleep can lead to daytime sleepiness, problems concentrating, and even more severe conditions like heart diseases, diabetes, etc. 
Nutrition and a balanced diet
Many nutrients are critical for the proper functioning of our bodies. Deficiencies in the following nutrients have been linked to fatigue 
- Vitamin B2 (riboflavin)
- Vitamin B3 (niacin)
- Vitamin B5 (pantothenic acid)
- Vitamin B6 (pyridoxine)
- Vitamin B9 (folate)
- Vitamin B12
- Vitamin D
- Vitamin C
Lack of them can lead to excessive fatigue and various medical conditions like anemia, depression, and neurological problems.
Maintaining a balanced diet with proper proteins, carbohydrates, and fats ratios is essential. An imbalanced diet can be a cause of fatigue as well.  Try to get a balanced diet high in nutrient-dense foods. It will help you maintain your energy levels and get all the nutrients your body needs. Undereating or eating ultra-processed food may result in deficiencies of nutrients and calories, leading to exhaustion. For example, diets high in added sugar can negatively impact sleep and result in chronically high levels of glucose and insulin, which can make you feel fatigued. Following a diet rich in foods like fruits, veggies, legumes, and protein sources like fish and eggs can provide you with optimal nutrition.
Consuming caffeine can give you an energy boost, but drinking too much of it or drinking it in the evening can impair your sleep. Caffeine is not only present in coffee but also in black or green tea. It can lead to trouble falling asleep and also lowers the quality of sleep.  Caffeine effects typically wear off 6-8 hours after ingestion, so avoiding it in the late afternoon is recommended. While coffee or caffeinated beverages like green tea can have some health benefits, energy drinks are very harmful. They are high in caffeine and other stimulants, with a substantial amount of added sugars.
Dehydration may lead to lower energy levels and decreased concentration.  Staying well-hydrated can help you maintain active and energetic throughout the day and prevent various medical conditions like reduced kidney function, urinary tract infections, kidney stones, hypertension, and even dementia. The recommended daily water intake is around 2.7 liters for women and 3.7 liters for men. However, it largely depends on physical activity, sweating, etc., so you might need to drink even more.
Although some stress is normal, if you are chronically stressed, it may lead to fatigue or even stress-related exhaustion disorder (ED). It is characterized by physical and psychological symptoms of exhaustion developed in response to long-term psychosocial stress. [6,7]
Paradoxically, if you are doing too little, you may also feel fatigued. People with a sedentary lifestyle who regularly complain of fatigue can increase their energy levels by 20 percent and decrease their fatigue by 65 percent by engaging in regular, low-intensity exercise. 
Certain medications have been linked to side effects like insomnia and increased tiredness. These include steroids, blood pressure medications (like beta-blockers), antihistamines, and antidepressants. [9, 10]
Medical conditions and fatigue
Various medical conditions are proven to cause fatigue.  Here are listed the most common ones, including other symptoms. Please discuss your health issues and changes to your course of treatment with your doctor first.
Anemia is the most common blood disorder, leading to impaired oxygen delivery to our bodies. Anemia can be caused by chronic blood loss (for example, GI ulcers), some nutrient deficiencies (iron, vitamin B9, and B12), and chronic diseases like diabetes or kidney diseases. Most commonly, it is caused by iron deficiency. It can affect various populations but most commonly presents in women of childbearing age due to blood loss during menstruation. If that’s the case, you can take iron supplements or eat food rich in iron, such as spinach, broccoli, and red meat. Vitamin C can also lead to better absorption of iron in the intestine.
Fatigue can be a symptom of infection, ranging from simple flu to HIV. Usually, they are accompanied by other symptoms like fever, headache, appetite loss, and some organ-specific symptoms (like diarrhea, cough, shortness of breath, etc.). Some of the infections most commonly linked to fatigue are flu, mononucleosis, COVID-19, cytomegalovirus, hepatitis, HIV, and pneumonia.
Various sleep conditions, like insomnia, sleep apnea, narcolepsy, etc., lead to excessive daytime fatigue and can also contribute to developing some other severe medical conditions. 
If you get tired from an activity that used to be easy, for example, walking up the stairs, it may be a symptom of some severe heart conditions like coronary artery disease or heart failure. It can even be life-threatening, so you should take care of it without delay.
Hormones produced by the thyroid gland control the rate of our metabolism. When their production is deficient, it can lead to fatigue, decreased sweating, cold intolerance, bradycardia, constipation, weight gain, etc. Hypothyroidism has various etiologies, but most commonly, it’s of autoimmune origin - Hashimoto thyroiditis.
A neurosensory disorder characterized by chronic pain. Aside from pain, patients complain of headaches, fatigue, sleep problems, and even fibro fog - a cognitive dysfunction with difficulties concentrating, poor memory, and lack of clarity in mind.
Chronic fatigue syndrome
CFS, also called myalgic encephalomyelitis, is a disease characterized by severe fatigue that lasts for at least six months. Fatigue worsens after physical activity, and sleep is unrefreshing. It also causes cognitive impairments. 
Other common conditions include allergic rhinitis, food intolerance, rheumatoid arthritis, autoimmune diseases, diabetes, obesity, cancer, multiple sclerosis, etc.
To improve fatigue, you first need to get to the bottom of what causes it. Commonly it is caused by inappropriate lifestyle decisions with a combination of our environment. You can easily improve it by taking simple steps such as improving your sleep hygiene, eating a healthy diet, or exercising regularly. If you have changed those factors but still feel fatigued, visit your doctor. Excessive tiredness can be a symptom of an underlying medical condition, ranging from mild to life-threatening.