The Immediate, Short-Term Health Effects of Sleep Deprivation

Just as we can’t live without food or water, we also can’t live without sleep. But while eating and drinking are voluntary actions, sleep is not: you can’t fight it.

When you deprive your body of quality sleep, you almost immediately set off a chain of short-term health effects. As sleep deprivation continues, you also risk coming face-to-face with serious long-term issues.

While ideal, it’s not always realistic to enjoy a perfectly balanced eight-hour sleep every night of the week. We have social commitments, jobs, kids and we get sick, all of which can throw our model sleeping patterns.

Today, we take a look at the immediate, short-term effects sleep deprivation can have on your heath. (Also keep an eye out for part two, where I’ll look at the long-term effects.)

Forgetfulness and distractions


There is a strong correlation between sleep deprivation and forgetfulness.

Memory is sometimes split into two sub-categories: visual working memory and verbal working memory. We want to focus on verbal working memory. This encompasses things we read and hear, and when we’re sleep deprived, memory formation is impaired and we struggle to recall facts and information.

Sleep is crucial to your brain’s ability to remember, retain and recall information. When you’re sleep deprived, you’re fighting against yourself when it comes to performance, regardless of whether that’s in an exam or during a regular workday.


Throughout the day, we face a multitude of distractions.

Whether that’s a co-worker distracting you from your current task or a friend distracting you on the phone when you’re trying to use the treadmill at the gym, distractions are all around us. Sleep deprivation can reduce your ability to focus and increase your likelihood of being distracted.

While it may not be a big deal if you get distracted in the kitchen, and let the water boil over in the pot, the outcome is completely different when you’re distracted while behind the wheel: up to 30% of road accidents are attributed to drowsy driving. That’s hardly an insignificant number.


Through sleep deprivation, performance is impaired in any and all aspects of day-to-day life, not just endurance activities like sport. That means performance can be impaired when you’re driving, when you’re at work, when you’re at the gym, or when you’re cooking dinner.

Reaction times

As a result of impaired performance, reaction times are slowed and can be impacted just as if your Blood Alcohol Concentration (BAC) was at 0.05, which is the legal limit in many countries all over the world, including France, Australia, Iceland, and Costa Rica.

It can also impact your decision-making abilities and decrease your tolerance for others – especially when driving.

The effects of sleep deprivation on your reaction times can be apparent after just one night of poor sleep. Imagine the effects after cumulative nights?

Irritability and loss of motivation

Sleep deprivation can have an almost immediate effect on your health. As we’ve discussed above, it affects cognitive actions as well as your brain’s ability to properly form memories and recall information.

Additionally, it can also have an effect on your happiness and quality of life. Irritability and loss of motivation are common outcomes of sleep deprivation. We look at each below.


Sleep deprivation doesn’t just affect you. When you’re craving the sleep you’re not getting, your moods can change, leaving you feeling annoyed and easily irritated. This extends to those around you, too, affecting relationships with friends, family, and colleagues.

Researchers at the University of Pennsylvania found through an experiment that subjects limited to four-and-a-half hours of sleep per night for a week reported feeling more stressed, angry, sad, and mentally drained than usual.

No one can understand how you feel except for you, so if you’re feeling more irritable, short-tempered, and anxious than usual, perhaps a lack of good quality sleep is to blame?

In a cruel never-ending cycle, anxiety and stress due to sleep deprivation leave you feeling agitated and aroused, thus making sleep harder.

Loss of motivation

A loss of motivation is a direct outcome of sleep deprivation, but could it also be something deeper? From depression and anxiety to hormonal imbalances, thyroid disease, and anaemia, there’s no one definitive cause for a lack of motivation.

You might feel like you’re in a slump at your job, with your friends, or with your partner, and sleep deprivation might only be one of the reasons behind it.

Sleep deprivation

As you may have noticed in the examples listed above, short-term effects of sleep deprivation more commonly seem to affect us physiologically, rather than physically. Could the lack of “visible” effects be one of the reasons people don’t take sleep deprivation as seriously as they should, allowing it to continue until more perceptible or “physical” effects are noticed?

Keep an eye out for the second part of this blog series, where I dive deeper into the long-term effects of sleep deprivation, including high blood pressure, depression, and weight gain.