Can Poor Sleep Make You Sick? Science Says Yes.

Ever wonder if sleeping less actually makes you more likely to get sick? The answer is: absolutely.

In one study, researchers tracked people’s sleep for two weeks, then exposed them to the common cold virus (yes, really). People who slept less than 7 hours were nearly 3 times more likely to get sick. And those with poor sleep efficiency—meaning they spent a lot of time in bed awake—were 5.5 times more likely to catch a cold.

Interestingly, how rested people felt didn’t matter. It was about how well and how long they actually slept.

What About “Too Much” Sleep?

In large-scale studies, you often see both short and long sleep linked to worse health outcomes—a “U-shaped” curve. That doesn’t necessarily mean long sleep is causing problems. It may just reflect that people who are unwell tend to sleep more.

Short sleep, on the other hand, has been shown to directly impact health in controlled experiments.

Fragmented sleep—waking up a lot during the night—also consistently shows up as a risk factor for disease and mortality.

Bottom Line

• Less than 7 hours of sleep? Not great.
  
• Sleep quality matters as much as quantity.
  
• Long sleep isn’t bad on its own—just a possible signal that something else is going on.
  

😷 Sick of getting sick?
Arcashift helps you sleep better and boost your defenses—by aligning your schedule with your body’s circadian clock.

Sources:

Cohen, S., Doyle, W. J., Alper, C. M., Janicki-Deverts, D., & Turner, R. B. (2009). Sleep habits and susceptibility to the common cold. Archives of Internal Medicine, 169(1), 62–67.

Zhu, M., et al. (2021). Sleep duration, fragmentation, and disease risk in 84,404 UK Biobank participants.

Wang, Y., et al. (2020). Sleep duration and mortality in adults with and without diabetes: 273,029 participants from multiple cohorts.