When Should I Worry About...

5 Ways Poor Sleep Affects the Body

Feb. 29, 2024 - Katie McCallum

There are an exhausting number of reasons for getting bad sleep, some of which are in your control. Did you really need another glass of wine after dinner, for instance? But other factors — from stressful life events to health-related issues that make it hard to fall or stay asleep — aren't as easy to correct.

Regardless of the reason, getting your sleep back on track is crucial for your mental wellbeing, daytime productivity, quality of life and overall health.

"I like to break down our health into four main categories — how we eat, how we move, how we interact socially and how we sleep," says Dr. Randall Wright, a neurologist who specializes in sleep medicine at Houston Methodist. "If any of these are off, the other categories suffer."

For instance, perhaps you've noticed how a night of bad sleep can ruin your workout. Or how irritable it can make you.

"We tend to think of sleep as a luxury, but it's a necessity," Dr. Wright stresses. "Not getting enough quality sleep affects everything."

Here are five ways poor sleep affects the body:

1. Mood

Irritability, a heightened sense of stress, lack of patience or attentiveness — these are all the more obvious ways that a night of bad sleep can affect your mood the next day. But Dr. Wright notes that the consequences also can be more consequential.

If poor sleep progresses into sleep deprivation, it can disrupt the balance of neurotransmitters and hormones that support your overall wellbeing, leading to mood instability, mental inflexibility and negative emotions.

"Not sleeping can contribute to anxiety and depression," says Dr. Wright. "What makes this more problematic is that it becomes a vicious cycle, since anxiety and depression can then make it harder to get good sleep. Both can also affect how you eat, move and interact socially, which, as mentioned, also affect sleep."

2. Physical performance

Your exercise routine should be challenging. But have you ever had one of those workouts where you're physically struggling more than what's normal? Not getting a good night's rest could be to blame.

"When it's a chronic issue, poor sleep can absolutely affect physical performance," says Dr. Wright. "Studies show sleep deprivation leads to delayed reaction time, poor motor control, reduced endurance and more."

And since sleep is crucial for muscle recovery and repair, inadequate amounts can keep your body from bouncing back as effectively or quickly after exercise — leading to sluggish workouts and even increased injury risk in certain cases.

(Related: Why Are Workouts So Hard Some Days?)

3. Decision-making

"Sleep deprivation leads to frontal lobe dysfunction, which can negatively affect impulse control and mental restraint," explains Dr. Wright. "When decision-making becomes poor, we tend to act rash and do things that aren't appropriate."

Maybe it's a decision that derails your efforts toward eating healthy or making time for exercise. But it could even mean making a choice that puts your physical well-being in immediate danger, while driving or working a job, for instance.

Sleep deprivation can also lead to cognitive biases, such as negative thinking patterns and rumination, which can exacerbate feelings of sadness, anxiety and irritability. All reminders of how closely tied sleep is with the other pillars of our health.

4. Immune system

The internal processes in your body suffer from poor sleep, too. While asleep, your body is highly active in the various restorative processes essential for your physical and mental health. For instance, getting enough quality sleep promotes a healthy immune system — helping the body more effectively manage inflammation and ward off harmful germs.

"More and more studies are showing that chronic sleep deprivation contributes to chronic inflammation," warns Dr. Wright. "This likely explains the connection we see between long-term sleep problems and the risk of certain cancers."

While acute inflammation can be helpful for the body at times, persistent, low-grade inflammation isn't — it's linked to high blood pressure, type 2 diabetes, heart disease, dementia, certain cancers and more.

5. Blood sugar regulation

It's critical for your body to regulate blood sugar levels throughout the day. This ensures your cells have the energy needed to perform important tasks, but also keeps excess sugar (glucose) out of the bloodstream, so it can't harm blood vessels and organs.

Blood sugar regulation remains important while you're asleep. In fact, it's a time when the body becomes more sensitive to insulin, the hormone responsible for transporting glucose into cells for energy or storage. A lack of sleep can disrupt the process.

"Disruptions to sleep patterns can also affect what's called your circadian rhythm, which is the body's internal biological clock that regulates many physiological processes over a roughly 24-hour period," explains Dr. Wright. "When our circadian rhythm is thrown off, it can lead to changes that, among other things, contribute to impaired glucose regulation."

What to do when poor sleep is affecting you

For the sake of your overall health, it's important to correct poor sleep.

Dr. Wright's tips for prioritizing good sleep hygiene include:

  • Getting seven to nine hours of sleep every night
  • Maintaining a regular sleep schedule, including when you have time off
  • Avoiding stimulating activities, like staring at your phone, before bed
  • Creating a sleep environment that's cool, dark, quiet and free of distractions
  • Following a wind down routine that helps you relax before bed

If you've tried the advice above and still aren't consistently getting good sleep, it's time to talk to your doctor.

"Sleep problems aren't one size fits all, so it's important to get to the bottom of what's driving yours," says Dr. Wright. "Poor sleep often comes down to correcting sleep hygiene issues, but not always."

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