There’s a lot we don’t know about sleep. Questions like why we have sleep cycles, why we dream and why humans even need sleep in the first place are ones scientists are still finding exact answers to.
But one thing’s for certain: when we sleep, and sleep well, we feel better physically and mentally, and perform better during the day.
Many biological processes happen during sleep:
- The brain stores new information and gets rid of toxic waste.
- Nerve cells communicate and reorganize, which supports healthy brain function.
- The body repairs cells, restores energy, and releases molecules like hormones and proteins.
These processes are critical for our overall health. Without them, our bodies can’t function correctly.
Let’s take a closer look at why we sleep, along with what happens if we don’t get enough.
What Happens When We Sleep ?
Energy conservation :
According to the energy conservation theory, we need sleep to conserve energy. Sleeping allows us to reduce our caloric needs by spending part of our time functioning at a lower metabolism.
Cellular restoration :
Another theory, called the restorative theory, says the body needs sleep to restore itself.
The idea is that sleep allows cells to repair and regrow. This is supported by many important processes that happen during sleep, including:
- Muscle repair
- Protein synthesis
- Tissue growth
- Hormone release
Brain function :
The brain plasticity theory says sleep is required for brain function. Specifically, it allows your neurons, or nerve cells, to reorganize.
When you sleep, your brain’s glymphatic (waste clearance) system clears out waste from the central nervous system. It removes toxic byproducts from your brain, which build up throughout the day. This allows your brain to work well when you wake up.
Research suggests that sleep contributes to memory function by converting short-term memories into long-term memories, as well as by erasing, or forgetting, unneeded information that might otherwise clutter the nervous system.
Sleep affects many aspects of brain function, including:
- Problem-solving skills
- Decision making
A healthy and strong immune system depends on sleep. Research Trusted Source shows that sleep deprivation can inhibit the immune response and make the body susceptible to germs.
When you sleep, your body makes cytokines, which are proteins that fight infection and inflammation. It also produces certain antibodies and immune cells. Together, these molecules prevent sickness by destroying harmful germs.
How Much Sleep We Need ?
- Birth to 3 months: 14 to 17 hours
- 4 to 12 months: 12 to 16 hours per 24 hours, including naps
- 1 to 2 years: 11 to 14 hours per 24 hours, including naps
- 3 to 5 years: 10 to 13 hours per 24 hours, including naps
- 6 to 12 years: 9 to 12 hours
- 13 to 18 years: 8 to 10 hours
- 18 to 60 years: 7 or more hours
- 61 to 64 years: 7 to 9 hours
- 65 years and older: 7 to 8 hours
What Happens If You Don’t Get Enough Sleep ?
Without enough sleep, your body has a hard time functioning properly. Sleep deficiency is linked Trusted Source to chronic health problems affecting the heart, kidneys, blood, brain, and mental health.
Lack of sleep is also associated with an increased risk of injury for both adults and children. Driver drowsiness, for example, can contribute to serious car accidents and even death.
In older adults, poor sleep is associated with an increased risk of falls and broken bones.
- Your body does a lot of important work while you’re asleep. Good sleep is vital for your physical and mental health, so if you’re having trouble falling asleep, staying asleep, not feeling rested when you wake up or feeling tired during the day, talk to your doctor about what you can do to improve your sleep.