Constantly sick? Get more sleep

People who slept less than six hours every night were 4.2 times more likely to catch a cold, researchers at University of California, San Francisco found in a new study.

"Sleep was the biggest overall factor in well being," said Aric Prather. "It didn't matter how old the people were, how stressed, education or income, their ethnic background, or whether they smoked. The amount of sleep they got was a fundamental factor in determining how healthy they were."

The effects of sleep deprivation and the benefits of getting enough sleep are an oft-repeated mantra among health experts. But in a society that prizes sleep deprivation as a sign of productivity and commitment to work, Prather told dpa, "we need more studies to really hammer home the point that sleep is crucial for our well-being."

Here are a few other studies that illustrate how risky it is when you don't have a good night's rest.

1. Memory and cognitive function are impaired

Beyond slowing our reaction times and hindering overall performance, lack of sleep actually has long term negative effects on our ability to learn, process new information, and on the functioning of our high cognitive abilities.

Dr. William Killgore at Harvard Medical School found in a 2010 study for the journal "Progress in Brain Research" that even when alertness and vigilance were restored, a person who was chronically sleep deprived also had difficulties with creative, innovative and "more divergent aspects of cognition."

In other words, while you may be able to pick yourself up and make good decisions at work after not sleeping for a week, you'll have trouble finishing that novel or painting or film.

2. Increased chances of obesity and metabolism problems

Several studies are currently in the works to determine whether sleeping longer can help you lose weight, as some studies have reported a connection between short sleep cycles and increased obesity.

Researchers have known for years that being obese can affect your sleep cycles: sleep apnea, a condition in which breathing is interrupted during sleep resulting in a loss of restorative REM sleep cycles, is often a sympton of obesity.

However, a 2013 study by Dr. Silvana Pannain and Dr. Gugliemo Beccuti at the University of Chicago Department of Medicine also found that short sleep cycles and poor sleep quality may also contribute to the development of obesity: Sleep is an important regulator of the body's metabolism functions, and less sleep means the body is less able to regulate how much it eats, leading to increased hunger.

3. Stress on the heart

A 2013 study found "a significant interaction" between sleep deprivation and blood pressure. Researchers tested a group of 20 healthy young adults who had previously not experienced any current or past sleep issues, and found that after one night of sleep deprivation, subjects' blood pressure went up, which in turn caused acute psychological stress. The stress on the heart and mind meant subjects did poorly in a series of standardized cognitive tests.