A Hillary Clinton supporter yawns while awaiting the arrival of the Democratic presidential nominee for a rally at John Marshall High School in Cleveland, Ohio, Aug. 17, 2016. Reuters

Americans are not getting enough sleep and it is making us fat and depressed. Insufficient sleep has been linked to various chronic diseases and conditions, including diabetes, cardiovascular disease, obesity and depression, according to the Centers for Disease Control and Prevention.

"Getting sufficient sleep is not a luxury—it is a necessity—and should be thought of as a 'vital sign' of good health," the government agency warns.

With the demanding holiday season coming up, and its flurry of parties, shopping, events and other reasons not to sleep a full night's rest, here are some health facts and tips to explain why you always feel tired and what you can do about to feel better physically.

1. Roughly 25 percent of Americans don't get enough sleep and 10 percent experience chronic insomnia.

2. Newborns should sleep up to 18 hours a day, preschool-aged children need 12 hours, older children need 10 hours, teenagers need nine hours and adults need seven to eight hours a day, according to the CDC.

3. If you are having a hard time sleeping, it's a good idea to keep a diary of your bedtime problems to later share with a doctor, the CDC suggests. You can write down when you go to bed, to sleep, wake up, get out of bed and take naps, among other facts.

4. Try to develop strong sleeping habits, such as going to bed at the same time and waking up at the same time each morning.

5. Don't eat a large meal before going to bed.

6. People with healthy sleeping habits tend to be married or have steady employment. Only half of divorced people, for example, get enough sleep, the CDC found.

7. Being white helps, which is likely a result of various economic and health factors associated with race. Non-Hispanic whites tend to sleep more soundly than non-Hispanic black residents, the CDC reported.

8. Not getting enough sleep is dangerous in many ways. For example, it's been tied to motor vehicle and machinery-related crashes that can result in death, injury and disability each year.

9. Health conditions such as recovering from surgery, anemia, depression, thyroid issues or pregnancy, can make it difficult to sleep. Taking medications such as antidepressants, antihistamines and medicines for nausea and pain can also make for restless nights.

10. Your diet can also make you feel tired. An iron deficiency can result in you feeling angry, weak and unable to focus. Eat some lean beef, kidney beans, tofu, eggs or peanut butter for energy.