1. You Always Feel Hungry

Lack of sleep influences hormone levels, including increasing the “hunger hormone” ghrelin and decreasing leptin, that is involved in satiety. By activating your endocannabinoid system, that is involved in modulating appetite and food intake, sleep deprivation can even give you the munchies, almost like marijuana use.

2. You’ve Gained Weight

One of the consequences of eating more when you are sleep deprived is weight gain, though lack of sleep also promotes metabolic dysfunction that further fuels weight gain. Losing as little as half-hour of sleep every night can disrupt your metabolism enough to cause weight gain. If you need eight hours of sleep but consistently only get seven, you may theoretically raise your risk of obesity by approx 34 % and at the same time increase your possibilities of insulin resistance — that is a hallmark of most chronic diseases, including type 2 diabetes — by 78%.

3. Your Memory Fails You

The process of brain growth, or neuroplasticity, is believed to underlie your brain’s capacity to control behavior, including learning and memory. However, sleep and sleep loss modify the expression of several genes and gene products that may be important for synaptic plasticity.

4. It’s Difficult To Make Decisions

Sleep deprivation leads to accidents both big and small, some of that prove to be fatal, partially because it leads to blunted reaction times and difficulty creating decisions.

5. Your Reaction Time Slows

In the aforementioned study, the researchers concluded that sleep deprivation is particularly problematic for decision-making involving uncertainty and unexpected change. This leads to blunted reaction times which can have tragic consequences while you are driving or on the job.

6. You’re Overly Emotional

Lack of sleep kicks your emotions into high gear, which means you are likely to overreact when expressing emotions like fear and anger. Your brain’s frontal cortex, for instance, plays a key role in the regulation of emotions, and sleep is vital for its function. Not to mention that research shows even one night of insufficient sleep may lead to unwanted behavior at work the next day, such as acting rude toward co-workers, theft or going home early without notifying the boss.

7. You’re always getting Sick

Sleep deprivation has a similar impact on your immune system as physical stress or illness, which may help explain why lack of sleep is tied to an increased risk of various chronic diseases and acute illnesses like colds and flu. In fact, research shows adults who sleep less than six hours a night have a fourfold higher risk of catching a cold when directly exposed to the virus than those who get a minimum of seven hours.

Sleeping less than 5 hours per night resulted in a 4.5 times higher risk. The study found that sleep was more important than any other factor when it came to protecting against the cold virus, including stress levels, age and smoking. In short, if you want your immune system to be at its best, adequate sleep is essential.

8. Your Vision Seems Unfocused

Even your vision is affected by lack of sleep. When you are tired your ciliary muscle, which helps your eyes focus, will not work up to par and “the extraocular muscles, that move the eye from side to aspect and up and down, may begin to track improperly, resulting in vision defect.” So, if you appear to be having trouble seeing after a night of little sleep, it’s most likely not in your imagination.

9. Your Physical appearance Suffers

Lack of sleep affects your physical look significantly, in part because it alters your hormonal balance, which can lead to acne, and decreases collagen production, which may increase the appearance of wrinkles.

10. You nod off during the Day

You might be able to fool your body into believing you can function normally on little sleep, however as reported in the journal Sleep, as soon as you let your guard down, overwhelming sleepiness ensues. Your body will likely cave into these episodes of “microsleeps” or nodding off, which can be tragic depending on your line of work or if you fall asleep while behind the wheel.