Sunday marks the beginning of Sleep Awareness Week, designed to bring awareness to the critical importance of getting the right amount and right quality of sleep.

Sairam Parthasarathy, MD, medical director of the Center for Sleep Disorders at Banner – University Medical Center Tucson, is an expert on why humans need sleep, how much sleep they need and how to determine if you are getting high-quality zzzzzs. Without uninterrupted, deep sleep, your physical, mental and emotional health can suffer.

“Sleep is very important — that’s because every part of the body needs to sleep,’’ said the University of Arizona physician, researcher and professor of medicine. “We know that the brain needs to sleep, but also, every tissue in the body. That’s everything ranging from the heart, the lungs, the immune system, even skin cells need sleep.’’

According to the National Sleep Foundation, adults need seven to nine hours of sleep each day.

But what about that anti-sleep drug, also known as caffeine?

Parthasarathy, a confirmed coffee drinker, says it is a good idea to avoid it before bedtime.

“(The) most key element of that is that not to have coffee or caffeine-containing product– be it tea, or chocolate, cocoa, or soda that contains caffeine– within four or five hours of sleep.’’

It’s not only the number of hours of sleep but the quality of those hours, he says.

 “So just like food, we need sufficient amount of food and we need sufficient quality of food. In the same way, we need the sufficient amount of sleep, as well as sufficient quantity of sleep.’’

Three groups of people are at the most risk when they don’t get enough sleep, he says. They are:

• High-intensity workers: Working extra-long shifts requiring extreme focus fatigues the brain just like any other muscle and make us more prone to errors. “It could be a pilot. It could be a truck driver,’’ Parthasarathy says. “It could be anyone who is doing high intensity work that requires constant vigilance and concentration,’’ he says.

• Hospitalized patients: Patients with cognitive problems can be more susceptible to sleep loss when hospitalized, he said. “They get delirious in the hospital. And this actually is independently associated with greater chance for death, greater chance for falls, and untoward outcomes.’’

• Elderly patients, especially those in nursing facilities: “With every passing hour from their long sleep sojourn that they had the previous night, their brain cells start accumulating sudden bad humors that interferes with the ability of the brain to carry out the processes,’’ he said.