With cold air surging across the country and snow lingering from several winter storms, the winter season is nearing.
But as this time of year ushers in less sunlight, colder air and holiday indulgences, it can have a significant impact on the human sleep cycle.
"Sleep is the time for the body to rest and repair itself and get ready for the functions of the day," Associate Physician in the Division of Sleep Medicine at Harvard Medical School Lawrence Epstein, M.D., said.
The amount of sleep each person needs varies by individual, but most people need between 7.5 and 8.5 hours of sleep each night.
1. Lack of Light
"The change in light can have a big effect on the time and quality of your sleep," Epstein said.
The amount of daylight during the winter is more limited than in the other seasons, impacting the body's cycles.
"Light directly impacts the pituitary, which secretes melatonin," Chair of the Homeopathy Department at Bastyr University's School of Naturopathic Medicine Dr. Brad Lichtenstein, N.D., said.
Melatonin regulates the body's sleep-wake cycles. Lack of light can cause the body to produce more of the chemical, making the body feel tired and sluggish.
In addition, lack of light during the winter months or during the transition from fall into winter can induce seasonal affective disorder (SAD). SAD is categorized by full-fledged depressive episodes that take place regularly during times of seasonal change.
2. Colder Air
Winter is notorious for an increase in utility bills as temperatures drop and heat gets turned on. However, heating can have undesirable effects on sleep quality.
When air is too cold, it will negatively affect melatonin production and cause the body's sleep cycle to be disrupted. However, air that is too dry or too warm will dry out the body's mucus membranes and make the body more susceptible to illnesses such as the cold or flu.
"When we are in an environment where we are heating the air that actually denatures the mucus membranes and makes them more susceptible to bacteria and viruses," Dr. Lichtenstein said.
3. Change in Eating Habits
Christmas cookies, along with other holiday sweets, can alter the body's hormone levels and, as a result, impact the sleep cycle.
While summertime brings forth natural sugars in the form of fruit, winter contributes hearty, dense carbohydrates to the table.
From Halloween through the Christmas and New Year's holidays, much of the winter season is based around sugary, fat-laden and high-calorie foods. These types of foods impact the body's hormone levels.
Associated with metabolism and appetite, the hormone leptin is also influenced by eating a surplus of these types of foods. The change in the levels of leptin in the body ends up disrupting the sleep cycle, and these disruptions will cause the body to further alter hormone levels.
"When our sleep cycle gets disrupted, we wind up craving those foods more and we don't know when we're full," Dr. Lichtenstein said. "If we continue to eat like this, it will affect our sleep... it's a vicious cycle."
The Consequences of Sleep Deprivation
According to Lichtenstein, in 1910 the average American slept between nine and 11 hours each night. By 2001, the average American slept only six hours.
Sleep deprivation is classified as a lack of sleep that affects a person's performance when awake. Symptoms of sleep deprivation can include having trouble staying awake during daily activities and the need for caffeine to get started.
This sleep deficit can lead to memory impairment, poor job performance and higher rates of motor vehicle accidents, according to Epstein.
According to Epstein, studies show that many who are sleep deprived tend to gain weight. Due to sleep's impact on glucose levels and the regulation of sugar metabolism, several studies have even found that it may be a precursor to diabetes.
It can also can bring on a weakened immune system, an increased risk for heart disease and hypertension.
According to Epstein, studies show that people who don't get enough sleep don't live as long.
"It really affects almost every aspect of good living, both how you feel and how your body functions," Epstein said.
To learn how to sleep better during the winter season, read the tips below from Lichtenstein.
2. Set the room temperature to be cool and comfortable, but not too dry.
3. Turn off electronic equipment an hour or two before going to bed.
4. Get moving or get some exercise everyday.
5. Try to relax before going to sleep.
6. Get some light exposure everyday.
7. Try not to eat three to four hours before going to bed.
Tropical Depression Two has formed in the Atlantic and could become the next tropical storm of the season by midweek.
Severe storms will rumble through parts of the Midwest, including Chicago, early Tuesday night.
Warm and humid air in place over much of the Midwest and Northeast at midweek will contribute to the risk of drenching, gusty and locally severe thunderstorms on Wednesday.
After temperatures briefly climb to typical midsummer levels, another cooldown will roll into the Midwest and expand to the East for the last part of July.
With the recent heat fading away, more relief will greet the Northwest by midweek in the form of rain.
Barrow, Alaska (1989)
Thunder reported for the first time since July 1982 (no rain fell with this so-called storm) July 1989 did go on to become the wettest July on record with more than 3 inches of rain.
Thompson, Manitoba (1990)
97 degrees -- record heat wave.
Bom Jesus, Brazil (1990)
About 1" of snow accumulated at elevation of 3,000; this is rare.