In general, most healthy adults need eight hours of sleep a night. In reality, America's adults snooze 6.9 hours each night, and 40 million suffer from sleep disorders.

No wonder many of us are cranky when we get up in the mornings!

When sleep is poor or inadequate, people feel tired or fatigued, their social and intimate relationships suffer, work productivity is negatively affected, and they make our roads more dangerous by driving while less alert. In fact, people who suffer from insomnia are absent from work at significantly higher rates and for longer periods than their teammates who sleep well. Some experts even say that insomnia costs companies $3,025 per employee each year.

What's more, couples who struggle with sleep apnea have higher divorce rates because the person listening to the snoring loses an average of 49 minutes of sleep a night - or 300 hours a year.

A sleep 'trifecta'

Many reasons exist for why people aren't sleeping well, but stress triggered by school or job pressures, family or marriage problems, and serious illness or death is the top culprit. Most people live lifestyles of speeding through the day, then abruptly turning off the light and expecting to turn on sleep instantly without a relaxing cool down time, sleep experts say.

In addition, people who are extremely overweight are more likely to get less than six hours of sleep on weeknights, suffer from frequent daytime sleepiness and are nearly six times as likely to be at risk for sleep apnea. Others at risk for tossing and turning are adults diagnosed with high blood pressure, arthritis, heartburn, or depression.

10 tips for sleeping well

Here are 10 tips from the National Sleep Foundation for getting a good night's sleep:

1. Maintain a regular going to bed and waking-up times, even on weekends, to keep your body's "circadian clock," which regulates your sleep-wake cycle, in sync.

2. Soak in a hot bath, read a book, listen to soothing music or engage in other relaxing activities just before bedtime.

3. Create a sleep-conducive environment free of interruptions by using blackout curtains, eye shades, ear plugs, "white noise," humidifiers, fans and other devices.

4. Sleep on a comfortable and supportive mattress and pillows.

5. Use your bedroom only for sleep and sex.

6. Finish eating at least 2-3 hours before your regular bedtime.

7. Exercise regularly, but at least three hours before bedtime.

8. Avoid caffeine six to eight hours before bedtime.

9. Avoid nicotine, such as cigarettes and other tobacco products.

10. Ditto for alcohol, which is not a sedative.