A woman is sleeping in a bed with a grey pillow and grey matching quilt. We see the back of her head, and her hair is up in a messy bun.

How Getting Enough Sleep Can Impact Your Immune System

by Liza Semenova

Whether you're an early riser or like to hit snooze a few times in the morning, sleep is an important part of our overall health. We spoke to Dr. Michael Grandner, PhD, MTR about why sleep is so important and how it impacts us, especially when it comes to our immune system. Currently, Dr. Grandner is the director of the Sleep and Health Research Program and of the Behavioral Sleep Medicine Clinic at the University of Arizona College of Medicine.

Tell us a little about your background

I am a clinical psychologist by training, but I have always worked in sleep and circadian research labs. I got my start at the University of Rochester where I worked in a sleep and neurophysiology research lab. As a graduate student at the University of California, San Diego and at San Diego State University, my work focused more on circadian rhythms, mental health, and sleep health. Then, as a postdoc at the University of Pennsylvania, this interest expanded to sleep and health more broadly. That is where I really started working with data linking sleep and diet/nutrition. Currently, my work at the University of Arizona looks at how sleep impacts the body, how social and environmental factors impact real-world sleep and strategies for improving sleep health at the community and population level.

We hear a lot about the circadian rhythm or sleep-wake cycle - what exactly is this and why is it important?

Our body is a finely-tuned machine, with systems, organs, tissues, and individual cells all performing their programmed functions in harmony together. This harmony is important because it is how different cells and systems stay in tune with each other and perform complementary work. As with every symphony, there needs to be a conductor that keeps time for the whole orchestra. The circadian system often serves as this conductor, keeping the heart, immune system metabolism, hormones, and many other body systems in line. The sleep-wake cycle is an important element, as it works on a circadian (day/night) rhythm and helps your body regulate most systems in the body. The sleep-wake cycle interacts with the circadian system to promote cardiometabolic, immune, hormonal, cognitive, and mental health.

Why is sleep important and how much sleep should the average person get? How much sleep should kids vs. adults get?

The typical adult should get about 7-8 hours of sleep on a typical night, but children need more. Depending on their age, they may require 8-12 hours per night. Younger children need more sleep, most school-age children should probably get 8-10 hours, and even adolescents should probably aim for 9 hours. It is important to get enough sleep so that your body has the time that it needs to do all the work that it has to do. Whether it's muscle growth and repair, or waste removal from the brain, or hormone production, your body needs sleep to perform these important jobs! 

How does enough (or lack of) sleep influence the immune system?

Sleep is closely tied to the immune system. People who do not get healthy sleep are more likely to get sick more often, have more severe forms of illness, get sick for longer, take a longer time to recover, and experience more fatigue and other problems. Several studies show that people who don't get enough sleep are more likely to catch colds, other viruses, and other infections as well. And lack of sleep even impacts vaccine effectiveness. In terms of systemic inflammation, lack of sleep leads to increased inflammation, which can, in turn, lead to metabolic and heart problems.

How does supplemental melatonin affect the sleep-wake cycle?

Melatonin is naturally produced in the body and released into the bloodstream during nighttime. It is a signal of night to the body and, among other things, helps support healthy sleep. Taking melatonin can sometimes help this process. Depending on the timing and dose, melatonin in the evening might help shift the nighttime a little earlier (leading people to feel sleepier at an earlier time than normal) and may reduce the time to fall asleep and promote sleep during the night. Taking melatonin supplements can help some people get to sleep faster, stay asleep longer, and have better quality sleep.


Need help catching Zzz's?Healthy‡ Sleep*"> Learn more about SmartyPants Healthy Sleep*, the perfect addition to any bedtime routine.

Show Comments

Looks Like You Need a Pick Me Up

Our delicious all-in-one vitamin supplements are packed with the nutrients you need to live the good life.

Shop smartypants vitamins

Liza Semenova