Sleep experts often liken sleep-deprived people to drunk drivers:

They don’t get behind the wheel thinking they’re probably going to kill someone.

But as with drunkenness, one of the first things we lose in sleep deprivation is self-awareness.

Sleep disturbance is among the most common sources of health problems in many countries.

Insufficient sleep causes many chronic and serious medical conditions that have an enormous impact on quality of life, not to mention the economy.

While no one knows why we sleep, it is a universal biological necessity; no animal with a brain can survive without it.

But how much sleep do we really need, how can we sleep better, and are there ways to cheat the system?

Research shows that there is a perpetual divide between what’s known to scientists and what most people do.

That’s why the American Academy of Sleep Medicine and the Sleep Research Society brought together a body of scientists from around the world to answer these questions through a review of known research.

They looked at the effects of sleep on heart disease, cancer, obesity and human performance.

One 2014 study of more than 3,000 people in Finland found that the amount of sleep that correlated with the fewest sick days was 7.63 hours a night for women and 7.76 hours for men.

So either that is the amount of sleep that keeps people well, or that’s the amount that makes them least likely to lie about being sick when they want to skip work.

Statistics are tough to interpret.

In another study researchers kept people just slightly sleep deprived－allowing them only six hours each night－and watched the subjects’ performance on IQ tests drop.

The crucial finding was that throughout their time in the study, the sixers thought they were functioning perfectly well, yet clearly they were not.

This finding has been replicated many times, even as many work fields continue to encourage and celebrate sleep deprivation.

In most professions it seems that companies are happy to have employees that work and never sleep.

But it is hard to think of another type of self-injury that might be similarly applauded.

The consensus: When we get fewer than seven hours’ rest, we are weakened (to degrees that vary from person to person).

When sleep persistently falls below six hours per day, we are at an increased risk of health problems.

Many people seem engaged in a daily arms race between wakefulness and unconsciousness, using various products to mask and manage poor sleep habits, and ultimately just needing more products.

Caffeine and other stimulants followed by a mix of relaxing sedatives.

Or alcohol, which only further messes with our natural body rhythms.

Effective sleep habits, like many things, appear to come back to self-awareness.

So how does one break unhealthy sleep habits?

Here are a few simple ideas that many experts recommend.

Try to keep a somewhat constant bedtime and wake-up time, even on weekends.

Keep caffeine use moderate, even if you don’t feel like a nighttime coffee affects you.

The same goes for cocktails.

Use screen wisely, too.

Remember that even on night mode, a phone or computer is shooting light into your brain.