Having trouble falling asleep and staying asleep? You're not alone. According to the Centers for Disease Control and Prevention, 50-70 million U.S. adults have a sleep or wakefulness disorder. Those sleepless nights can be as frustrating as they are devastating to your overall health, leading to such issues as headaches, hypertension, an increased risk for infection, memory decline and a greater risk of falls.

There are a number of sleep stealers that could be robbing you of a good night's sleep, and the culprit can often be identified by when your sleep troubles start.

Trouble falling asleep?

Environmental issues are a prime reason that many people have trouble falling asleep, and the good news is that these are things you can control. Set the scene for a good night's sleep by making sure your bedroom is dark, quiet and cool. (The National Sleep Foundation recommends a temp around 65 degrees Fahrenheit.) Avoid caffeine, alcohol (more on this later) and heavy meals in the hours before you go to sleep. Turn off anything with a screen (TV, phone, iPad) for at least an hour before bed and try to set up a pre-bed ritual that will cue your body that it's time to nod off. This can be as simple as brushing your teeth, washing your face and spending 10 minutes reading a magazine before you turn off the light.

Stress is another big sleep stealer, according to the American Psychological Association. If stress or anxiety are keeping you from falling asleep at night, try meditation, yoga or reaching out to a friend, counselor or your health care provider for help dealing with your issues.

Trouble staying asleep?

It's pretty normal to wake up a few times throughout the night. The natural sleep cycle lasts around 90 minutes, and many people wake up between cycles to go to the bathroom or get a drink of water. But if your sleep is disturbed throughout the night and you have difficulty getting back to sleep, you may be suffering from middle insomnia.

Age is a big factor here. As Dr. Marni Amsellem, a clinical psychologist who specializes in sleep promotion, explains: "Changes happen to our circadian rhythms (internal cues affecting the timing of our physiological processes such as sleep and waking) as we age." These rhythms shift as we age, so we get tired earlier and also wake up earlier than usual.

There are also a number of medical conditions that could be causing you to wake up throughout the night. Gastroesophageal reflux disease (GERD) causes an upwelling of stomach acids that may burn the esophagus at night. Another problem could be obstructive sleep apnea, which is a collapse of the upper airway during sleep, according to Dr. Michael Howell, co-founder of the Sleep Performance Institute. If your partner complains about your snoring at night, if you feel like you stop breathing throughout the night, or if you're often very tired when you wake up in the morning, Howell advises checking in with your healthcare provider to see if obstructive sleep apnea could be the culprit.

Waking up too early?

man awake in bed in middle of the night Waking up too early could be a sign of depression, while waking up at the same time may be due to alcohol. (Photo: Photographee.eu/Shutterstock)

Late insomnia is another sleep stealer. But in this scenario, it's the kind that wakes you up much earlier than you would have liked and keeps you from getting any more zzz's. According to the National Sleep Foundation, this type of insomnia is often linked to depression.

If you wake up at the same time every night — like say, 4 a.m. — or you consistently wake up after the same number of hours of sleep, your nightly cocktail might be to blame. That's because alcohol plays the role of a double agent during sleep. Initially, it can help you relax and nod off, but once your body has had a chance to metabolize it, your brain gets stimulated and sleep quality suffers.

The length of time it takes your body to break down alcohol may vary depending upon how much you weigh and how much you've had to drink. But if you consistently have the same amount of alcohol at around the same time each evening, it's going to wake you up at a predictable interval each night.

Is it time to get help?

If you've tried all of the tricks to improve your sleep, but you're still not having any luck, it may be time for a visit with your doctor. "While restless sleep or persistent snoring may seem harmless, chronic sleep deprivation can reduce your body’s resistance to infection and increase your risk of for more serious medical conditions," said Dr. Teofilo L. Lee-Chiong Jr., a professor of medicine at National Jewish Health in Denver and the University of Colorado Denver School of Medicine. "There are many consequences of disturbed sleep, such as impairments in attention, memory, response time and performance, increased risk of falls, and greater use of healthcare resources," he added.

If your sleep is suffering, get some help. You'll most definitely rest easier if you do.