You probably know that when it comes to health and productivity, sleep is a critical factor. But most people get some things wrong when it comes to their restorative time between the sheets. That's according to Dr. Robert Oexman, director of the research firm Sleep to Live Institute. Here are several common misconceptions about sleep, he says.

1. Myth: Diet and exercise are the main factors affecting the reason you can't lose weight.

Truth: People who don't get enough sleep have a more difficult time shedding unwanted pounds. A famous study which followed roughly 60,000 nurses for 16 years found that women who slept five hours or less nightly were 15 percent more likely to become obese, compared to those who slept seven hours a night. In fact, the females who slept less also had 30 percent higher risk of gaining 30 pounds over the length of the study, compared to those who slept more.

2. Myth: Reading is a great way to fall asleep.

Truth: The problem isn't the book, but the table lamp which lets you see it. Artificial lights emit blue light which suppresses a person's circadian rhythm and the secretion of the sleep hormone melatonin.

3. Myth: Watching TV in bed is relaxing and helps a person fall asleep.

Truth: Electronic devices of all sorts--TVs, tablets and laptops--all emit considerable amounts of blue light and should be banished from your bedroom, or at least not used two to three hours before you want to fall asleep.

4. Myth: There's no harm done as long as you can manage the symptoms of sleep deprivation.

Truth: While coffee or energy drinks may keep your eyes open on the road or at work, there are health consequences to not getting enough sleep. On the list: Increased risk of infection, heart disease, diabetes, weight gain, certain forms of cancer, depression, anxiety and accidents.

5. Myth: You can make up a sleep deficit on the weekend.

Truth: The consequences of not getting enough sleep during the week are felt immediately, so "catching up" isn't going to improve your outcomes if your habits and schedule during the week never change.

6. Myth: The older you get, the less sleep you need.

Truth: Older people need the same amount of sleep as their younger counterparts, it's just harder to get thanks to medications, pain and health issues such as depression. "We actually need to spend more time in bed as we get older to get the quantity of sleep we need, not less time in bed," he says.

7. Myth: Sleeping separately is an adequate fix for a snoring partner.

Truth: Not only does he believe sleeping alongside a mate is good for a relationship, Dr. Oexman likens separate bedrooms to building another kitchen for a mate with diabetes and ignoring his or her unhealthy eating habits. Sleep apnea--a disorder which involves pauses in breathing--has serious health ramifications and often lies at the root of snoring. If a partner snores disruptively, he or she should be evaluated by a health provider. If sleep apnea is not the cause of snoring, many devices exist to help stop the noise. "There's a little oral appliance that looks like a mouth guard that pulls the jaw forward and opens the airway," he says. "They're highly effective and work extremely well."