high-quality sleep—a minimum of
seven hours of sleep per night, according to the Centers for Disease Control and Prevention
(CDC)—is essential to maintaining a healthy body and mind. Yet as
the Cleveland Clinic points out, sleep deprivation is a common problem,
affecting between 50 million to 70 million adults in the U.S. at any given
time. "Virtually every human being experiences
sleep deprivation at some point in their life," their experts write.
For those with suboptimal sleep, the health consequences can be severe
and wide-ranging. In fact, studies have shown that getting less than the
recommended amount of sleep can significantly increase
your risk of death. Read on to learn what happens to your body if you sleep less than six
hours a night, and to find out why a good night's rest is one of the
very best things you can do for your health.
Getting less than the recommended amount of sleep can result in symptoms
that range from mild to severe—and
cardiovascular symptoms are some of the most dangerous among them, experts say.
"Insufficient sleep results in increased activity of the sympathetic
nervous system, leading to increased heart rate, vasoconstriction, and
elevated blood pressure levels," explains Taryn Fernandes, MD, a
supervising physician at
MEDvidi, an online mental health treatment center. "Lack of adequate sleep
has been linked to a higher risk of developing hypertension, as well as
cardiovascular diseases like stroke, coronary heart disease, and myocardial
infarction," she adds.
Additionally, getting the recommended seven to nine hours of sleep per
night is vital for regulating
the body's hormonal balance. "Sleep deprivation can interfere with the normal production of hormones
like cortisol, insulin, and growth hormone," Fernandes says.
Rigved Tadwalkar, MD, a
board-certified cardiologist at Providence Saint John's Health Center in Santa Monica, CA, says
sleep can interfere with your hormones in other ways, as well. "Indirectly,
poor sleep contributes to the disregulation of hormones implicated in
hunger," he tells Best Life. "This contributes to obesity, which
is a strong risk factor for cardiovascular disease."
Sleep deprivation can also have an outsized impact on your mental health, says Fernandes.
Specifically, getting inadequate sleep has been linked with higher incidence
of anxiety, depression, and other mood disorders.
"Lack of sleep may increase susceptibility to psychiatric disorders,
such as bipolar disorder and schizophrenia, since sleep plays a crucial
role in memory consolidation, emotional regulation, and cognitive functioning,"
explains Fernandes. She notes that regularly getting less than six hours
of sleep per night can cause mood swings, irritability, and decreased
Since sleep is important in maintaining a healthy immune system, sleeping
less than six hours per night could also translate into more frequent
sickness. "During sleep, the body produces cytokines, a type of protein
that aids in fighting infection, inflammation, and stress," explains
Fernandes. "Lack of sleep can lower the production of cytokines,
which can weaken the immune system and increase vulnerability to illnesses."
In fact, studies show that when you slash your sleep hours for even a few
nights at a time, you produce a reduced immune response—even if
you make up for your lost sleep later. "Restricting sleep to four hours per night for six days, followed by sleep for 12 hours per
night for seven days, resulted in a greater than 50 percent decrease in
production of antibodies to influenza vaccination, in comparison with
subjects who had regular sleep hours," writes the Centers for Disease
Control and Prevention (CDC).
Sleep is essential for optimal brain function, including memory consolidation,
learning, and creativity. "Normally, a good night's sleep literally
allows for repair and restoration of brain function to the levels seen
at the beginning of the prior day," explains David Merrill, MD, PhD, a
geriatric psychiatrist and director of the Pacific Neuroscience Institute's Pacific Brain
Health Center in Santa Monica, CA.
Merrill tells Best Life that the brain's "specialized cleaning
system," known as the glymphatic system, is most active during the
deepest stages of sleep. When the glymphatic system becomes dysfunctional,
neurotoxic waste products can accumulate in the brain, leaving you more
vulnerable to dementia.
"Sleep disturbances increase dementia risk, but unfortunately, dementia
itself can also lead to sleep disturbances," Merrill says. "So
you can end up with sleep worsening memory to the point of dementia, which
then worsens sleep. In this way, disrupted sleep can be part of a downward
spiral, making it all the more important to identify and treat sleep issues
during early and mid-life adult development. Ideally, sleep will be optimized
years before the potential onset of dementia. The hope is that with improved
sleep, we can actually delay the age of onset of dementia. The goal of
improving sleep is to extend a person's health span for as long into
their life as possible," he adds.
It should come as no surprise that you may feel tired or fatigued after
getting too little sleep—but you may be surprised by just how pronounced
your lethargy may be. The Cleveland Clinic points out that
fatigue from poor sleep can cause very disruptive symptoms that interfere with even the most routine
For some people, this can lead to an increased incidence of injury or accidents—including
car accidents. According to a 2018 study published in the journal BMC
Medicine, "sleeping six hours per night was associated with a 33 percent increased crash risk, compared to sleeping
seven or eight hours per night."
According to Besty S. Jacob, a Florida-based optometrist at
True Eye Experts, inadequate sleep can also negatively impact your ocular health.
"Sleeping less than six hours can lead to dry eyes, dark circles,
and blurry vision. This is because when we don't get the proper amount
of rest, our body does not produce tears as efficiently," says Jacob.
"This leads to increased friction in the eye which causes redness
and irritation and can eventually lead to more serious conditions such
as conjunctivitis or blepharitis," he adds.
Sleep deprivation has been linked with increased risk of developing a metabolic
disease such as Type 2 diabetes. It also contributes to poorer outcomes
for individuals who have already been diagnosed with a metabolic disease.
"If you get less than seven hours of sleep per night regularly, your
diabetes will be
harder to manage," explains the CDC. They note that too little sleep can increase
insulin resistance, make you feel hungrier, make it harder to maintain
a healthy diet and weight, and can raise your blood pressure. Since hypertension
twice as likely in those with diabetes, this can pose a danger to those already at high
risk of the condition.
Finally, you may notice that getting less than six hours of sleep per night
hinders your physical endurance. "Not only does quality sleep play
a role in overall health and wellness, but it is also crucial to optimal
performance—in athletics and life in general," explains Vernon
Williams, MD, a
sports neurologist, pain management specialist, and founding director of the Center for Sports
Neurology and Pain Medicine at Cedars-Sinai Kerlan-Jobe Institute in Los Angeles.
"Studies have shown that getting less than six hours of sleep at night
is associated with decreased time to physical exhaustion, reduced aerobic
output, reduced peak and sustained muscle strength, impaired metabolic
capabilities, and increased injury risk," he adds.
In fact, Williams says that sleep health and optimization of sleep efficiency
may be the most effective intervention a person can make to "optimize
their overall performance, whether on a sports court, in a classroom,
or at work."