Rest and the Endocrine System
What Is Fatigue?
Suppose you wake up at 6:30 a.m. to get ready for school. Classes begin at 7:45 a.m. and continue throughout the day until almost 3:00 p.m. After school, you have band practice until 5:30 p.m. Then you have to go home and help get dinner ready. After you help clean up after dinner, you have to start your homework. You finish your homework around 10:00 p.m. Since you have not had much time to relax today, you get on the Internet and chat with some of your friends or start playing a video game. You do not go to sleep until midnight. You often go through your day feeling like you have no energy, and you definitely have a lack of motivation to get some tasks completed.
If you are feeling this way, you are experiencing fatigue. Fatigue is physical and/or mental exhaustion. Do not confuse fatigue with drowsiness.
Drowsiness is feeling abnormally sleepy through the day. Drowsiness can be a symptom that goes along with fatigue. Fatigue is a normal response by the body due to lack of sleep, physical overexertion, improper diet, poor physical conditioning, depression, certain diseases, or emotional stress.
Causes of Fatigue
There are many factors that can cause fatigue, both mental and physical. How many causes of fatigue can you identify? In this interactivity, take a moment to review possible causes of fatigue and determine which ones you should be aware of if you ever experience physical and/or mental exhaustion. Click the player button to begin.
View a printable version of the interactivity.
Solutions for Fatigue
Fatigue affects your health in many ways. Poor concentration, simple errors, and forgetfulness are all effects of fatigue. For example, tasks may be started and not completed, or you put things down and later forget where you put them. It can affect your central nervous system by slowing down your reflexes. Slower reflexes can result in sports-related injuries or automobile accidents. Fatigue can lead to heart disease and muscle weakness because you do not have the motivation to be active, which can lead to a sedentary lifestyle. A sedentary lifestyle is a way of life that involves very little to no physical activity. Headaches, dizziness, and loss of appetite are also ways that fatigue can affect your health. In this interactivity, explore various solutions for fatigue. Click the player button to begin.
View a printable version of this interactivity.
The Importance of Sleep
Sleep allows the body to renew cells and maintain immunity. Research also has found that memories of the day become consolidated and filed during sleep. If someone does not get adequate sleep one night, the brain makes up for the loss by increasing the amount of REM sleep during the next night. Making up for deprived REM is called REM rebound.
How much sleep do you need? The average number of sleep hours needed varies according to age. Infants spend the majority of their sleep in REM. Conversely, teens need a great deal of sleep, but often do not get a sufficient amount. Teens need nine or more hours of sleep a night. Teens need more sleep than adults because of their fast growth physically, intellectually, and emotionally. Teens experiencing a lack of sleep would experience a decrease in performance, reaction time, learning, and concentration. Teens would see an increase in mood problems, behavior problems, accidents, injuries, and memory lapses.
Whether you are involved in athletics, have an after-school job, or spend your evenings doing homework, it is vital that you get nine or more hours of sleep a night. When you are well rested, you perform better in school, athletics, work, and other daily activities.
Sleep deprivation is common among today’s teens. Research revealed that adolescents experience a unique shift in their circadian rhythm. Research further indicated that this age group often does not get drowsy until around 11:00 p.m. Given that adolescents need nine hours of sleep, their bodies want to wake up at 8:00 a.m. These findings prompted many school systems across the country to change the start time of school.
The chart below indicates the number of hours the National Institutes of Health suggest someone gets at each phase of their life. This data was updated by the NIH in 2012. Are you getting enough sleep each night? If not, it is important that you change your sleep habits.
| Age | Suggested Amount of Sleep |
| Newborns | 16–18 hours per day |
| Preschool-aged children | 11–12 hours per day |
| School-aged children | At least 10 hours per day |
| Teenagers | 9–10 hours per day |
| Adults (including elderly) | 7–8 hours per day |
Sleep Cycle
How does sleep occur? What do your body and brain do while you are sleeping? These questions are answered by studying the sleep cycle. Sleep does not actually occur linearly, but rather as a cycle composed of different phases. Each phase of sleep has distinct characteristics, and some of the phases repeat within the cycle. In this interactivity, explore the sleep cycle and the impacts it has on you and your brain. Click the player button to begin.
View a printable version of the interactivity.
The Endocrine System
Your endocrine system is a collection of glands that produce hormones that have many functions. The endocrine system regulates metabolism, growth and development, tissue function, sexual function, reproduction, and sleep. Hormones are secreted in certain stages of the sleep cycle. A lack of proper sleep affects the functioning of the endocrine system and its ability to secrete important hormones to keep the body functioning properly. In this interactivity, learn about the endocrine system. Click the player button to begin.
View a printable version of the interactivity.
Health Risks That Affect the Endocrine System
There are numerous diseases that can affect the endocrine system, such as diabetes, a chronic disease that affects the pancreas. Individuals who are diagnosed with diabetes do not produce enough insulin in their bodies or may not produce any insulin at all. There are three forms of diabetes: Type 1 diabetes, Type 2 diabetes, and gestational diabetes.
Fortunately, Type 2 diabetes is largely preventable. Some of the predictors of Type 2 diabetes include stress, high cholesterol, and family history. The most significant predictor, however, is obesity. Having an unhealthy amount of body fat decreases the body's ability to properly use insulin. This is one of the many reasons why it is important to maintain a healthy and physically active lifestyle.
Graves' disease is the most common cause of hyperthyroidism, a condition that causes your thyroid to produce and release more thyroid hormone than your body needs. Hypothyroidism is a condition in which the thyroid does not produce enough thyroid hormone to keep the body functioning properly. Hypothyroidism can be caused by a variety of factors, including damage to the pituitary gland, inflammation of the thyroid, and radiation treatment.
Fatigue and Rest Review
Now that you have studied fatigue and rest, review your knowledge in this non-graded activity. Click the player button to get started.