Fatigue is a feeling of tiredness and lack of energy. The tired feeling of fatigue is often accompanied by a lack of motivation to partake in daily tasks and activities. Often, afternoon fatigue occurs as a normal response to personal and environmental triggers.
Increased Stress
Stress is a normal nervous system response to an anticipated difficult situation. The stress response causes the hypothalamus to trigger the adrenal glands to produce and releases excess amounts of the hormones cortisol and adrenaline. These hormones cause an increase in heart rate, breathing, blood pressure and metabolism. The stress response also allows the blood vessels to dilate to allow more blood to flow through the body. Situations that trigger the stress response are referred to as stressors. When a person is constantly exposed to stressors or the stress response does not turn off properly, stress levels remain high. This causes the body to consistently remain on alert, which exhausts the body and weakens the immune system, according to Kids Health. Over time, this prolonged stress response will cause a number of symptoms, including afternoon fatigue.
Dehydration
Water is essential to human life. According to the book "Nutrition and You" by Joan Salge Blake, a person could survival several weeks without foods but only live for a few days without water. Dehydration occurs when the body loses more water than it takes in. According to MayoClinic.com, humans lose more than 10 cups of water per day by sweating, breathing and elimination of waste. Electrolytes, which are important in fluid balance, are also lost with the water. Dehydration occurs when the lost fluid is not replaced through water consumption. As dehydration progresses during the course of the day, it can cause afternoon fatigue. In addition to fatigue, dehydration also results in a dry mouth, sleepiness, thirst, decreased urine output, headache and lightheadedness.
Malnutrition
Malnutrition occurs when the body does not receive enough nutrients. Malnutrition can occur as a result of an unbalanced diet or digestive conditions that impede proper absorption. According to MedlinePlus, symptoms of malnutrition vary based on which nutrient is deficient, but one of the most common symptoms of malnutrition is fatigue. The body requires food for energy. If food is not consumed throughout the course of a day, the body will become exhausted and a person will experience low levels of energy and afternoon fatigue.
Insomnia
Insomnia is a sleep disorder characterized by an inability to fall asleep or an inability to stay asleep throughout the night. Adequate sleep is an important part of proper body function. According to the American Academy of Family Physicians, adults need seven to eight hours of uninterrupted sleep every night. During sleep, the body re-energizes itself and prepares for the following day. An inadequate amount of sleep can cause a variety of physical and mental symptoms. A lack of sleep can lead to afternoon fatigue and irritability. It can also lead to confusion and difficulty concentrating.
References
- Kids Health: Stress
- Mayo Clinic: Dehydration
- MedlinePlus: Malnutrition
- American Academy of Family Physicians: Insomnia
- "Nutrition and You"; Joan Salge Blake; 2008
