Research suggests our brains depend on a nightly bath to keep them functioning at their best.

Tossing and turning the night before a big presentation at work, or going without sleep for reasons you just can’t explain – there’s little doubt that failure to get a good night’s sleep leaves you groggy and dazed, at best. But the cognitive effects of sleep deprivation, whether you miss an entire night or just an hour each evening, could cost you in ways you never imagined.

Evidence from University of California–San Diego researchers suggests sleep times are directly linked to earnings. Their findings, currently under review, found that sleeping one extra hour each night increased average earnings by 16 percent. For their average study participant, this meant an extra $6,000 per year.

It's a little hard to believe there's such a thing as sleeping too much, since so many of us feel like it's a struggle to even get barely enough.

But it's true: You can overdo it on sleep.

While it's tough to pinpoint the "just right" amount, most adults need between seven and nine hours a night to feel and function their best.

Regularly logging more than nine hours of sleep a night may be a sign of an underlying medical condition, but it also puts you at risk for a whole host of health concerns. Here are some of the biggest risks of catching too many Zzs.

Ideally, we would get the appropriate amount of sleep to keep our bodies healthy, but in our modern society things like jet lag, extended work hours, or using electronic devices cause disruptions in our sleep/wake cycle often leading to fewer hours of quality sleep. Most people suffer from chronic sleep restriction rather than complete deprivation, but there are very few studies that explore the effects of sleep restriction. Amita Sahgal and Aalim Weljie from the University of Pennsylvania and Peter Meerlo, from the University of Groningen in The Netherlands, investigated at how chronic sleep restriction affects the body's metabolic processes. Their work is published in the Proceedings of the National Academy of Sciences.

Simply taking a couple of naps may counteract the impact of a sleep-restricted night on stress and immune markers, a finding that could potentially benefit night and shift workers or other chronically sleep-deprived populations, the results of a French study indicate.

Brice Faraut, PhD, from the Université Paris Descartes-Sorbonne Paris Cité, France, and colleagues found that, after a night with only 2 hours of sleep, taking two naps of just 30 minutes each appeared to normalize levels of cytokines and catecholamines.

"Napping as a countermeasure to sleep restriction could, in addition to benefits on alertness, improve neuroendocrine stress and immune recovery, with a potential prophylactic long-term effect on cardiovascular health," the researchers write.

Do you have chronic sleep problems? You may be able to significantly improve your ability to get a restful night of sleep by practicing a popular form of meditation, a rigorous new study shows.

The findings may be particularly relevant to Americans older that 55, about half of whom have some form of sleep trouble. The research, a clinical trial published in the journal JAMA Internal Medicine, recruited about 50 older adults with moderate sleep problems and assigned them to follow one of two programs.

If you've ever been jolted awake by your alarm clock but were so momentarily confused that you reached for the telephone instead of hitting the snooze, you likely experienced an episode of what's called "sleep drunkenness." And you're not alone.

In a new study, researchers found that sleep drunkenness may affect one in every seven people. The disorder causes a person to be so confused upon being woken up that they don't know what they are doing.

The study, published Monday in the journal Neurology, also determined that 84 percent of people who experienced an episode of sleep drunkenness also suffered from a related sleep disorder, a mental health disorder or were taking psychotropic drugs such as antidepressants.

We've known for some time that sleep deprivation is associated with decreased productivity and a lack of focus, but that's not the end of the story: Insufficient sleep is also linked with less innovation, lower job satisfaction and unethical behavior in the workplace.

At last week's Corporate Sleep Health Summit, hosted by Harvard Medical School, some of the country's top sleep researchers and corporate leaders came together to discuss the latest research on the damaging impacts of sleep deprivation on American workers and corporate bottom-line objectives. But more importantly, the discussions raised important questions about how we can create a movement to improve sleep health. How can we make sleeping four hours a night go the way of the two-martini business lunch or smoking in the boardroom? The summit aimed to offer solutions to the sleep-deprivation crisis that's harming our health and our businesses.