You're not alone.
A study from the National Sleep Foundation finds that, among married people or couples living together, one-in-four adults skip or avoid sex because they're too tired.
It's no wonder. The workday can extend long into the night, many couples have children and pets to tend to, and everyone has diversions that draw their attention away from their partners -- and toward sleep.
CBS News Medical Correspondent Dr. Jennifer Ashton said on "The Early Show" not sleeping enough and not sleeping well is not OK. As a matter of fact, she noted, there is quite a price to pay in life and between the sheets.
Ashton, citing the National Sleep Foundation's figures, said roughly one-third of adults in all ethnic groups report getting less sleep on workdays and weekends than they need to function at their best. In addition, about one-fourth of all respondents say their current work schedule doesn't enable them to get enough sleep.
So how much sleep do people need?
Ashton said, "The first thing experts will tell you about sleep is that there is no 'magic number.' Not only do different age groups need different amounts of sleep, but sleep needs are also individual."
However, she added, sleep experts say most adults need between seven and nine hours each night for optimum performance, health and safety.
"When we don't get adequate sleep, we accumulate a sleep debt that can be difficult to 'pay back' if it becomes too big," she said. "The resulting sleep deprivation has been linked to health problems, such as obesity and high blood pressure, negative mood and behavior, decreased productivity, and safety issues in the home, on the job, and on the road."
Some of the common causes of sleep loss cited in the study include anxiety, illness, environment, medications and longer work days.
Illness, in particular, can cause loss of sleep.
Ashton cited insomnia -- the most common sleep complaint among Americans -- as a big factor.
She explained, "It can be either acute, lasting one-to-several nights, or chronic, even lasting months or years. When insomnia persists for longer than a month, it is considered chronic."
According to the National Center for Sleep Disorders Research at the National Institutes of Health, about 30 to 40 percent of adults say they have some symptoms of insomnia within a given year, and about 10 to 15 percent of adults say they have chronic insomnia.
Insomnia can be a disorder in its own right, but often it is a symptom of some other disease or condition, Ashton said.
Half of all those who have experienced insomnia blame the problem on stress and worry, according to the National Sleep Foundation.
If you have difficulty sleeping, Ashton said, it is essential to determine whether an underlying disease or condition is causing the problem. Sometimes insomnia is caused by pain, digestive problems or a sleep disorder. Insomnia may also signal depression or anxiety.
Sleep apnea and obstructive sleep apnea is also a disorder that can cause sleep loss. Sleep apnea is when breathing is briefly and repeatedly interrupted during sleep. Ashton explained the "apnea" in sleep apnea refers to a breathing pause that lasts at least ten seconds. Obstructive sleep apnea occurs when the muscles in the back of the throat fail to keep the airway open, despite efforts to breathe. Another form of sleep apnea is central sleep apnea, in which the brain fails to properly control breathing during sleep.
Obstructive sleep apnea is far more common than central sleep apnea.
Other sleep wreckers, according to the National Sleep Foundation, include thyroid problems, prostate problems that lead to frequent visits to the bathroom at night, depression, and some medications.
For more on sex and sleep, go to Page 2.
But all is not lost. Ashton suggested these WebMD tips to getting more sleep to improve your sex life.
• Cut the caffeine.
Simply put, caffeine can keep you awake. It can stay in your body longer than you might think - the effects of caffeine can take as long as eight hours to wear off. So if you drink a cup of coffee in the afternoon and are still tossing at night, caffeine might be the reason. Cutting out caffeine at least four to six hours before bedtime can help you fall asleep easier.
• Avoid alcohol as a sleep aid.
Alcohol may initially help you fall asleep, but it also causes disturbances in sleep resulting in less restful sleep. An alcohol drink before bedtime may make it more likely that you will wake up during the night.
•Relax before bedtime. Stress not only makes you miserable, it wreaks havoc on your sleep. Develop some kind of pre-sleep ritual to break the connection between all the day's stress and bedtime. These rituals can be as short as 10 minutes or as long as an hour.
Some people find relief in making a list of all the stressors of the day, along with a plan to deal with them this can act as "closure" to the day. Combining this with a period of relaxation perhaps by reading something light, meditating, aroma therapy, light stretching, or taking a hot bath can also help you get better sleep. And don't look at the clock! That "tick-tock" will just tick you off.
•Exercise at the right time for you.
Regular exercise can help you get a good night's sleep. The timing and intensity of exercise seems to play a key role in its effects on sleep. If you are the type of person who gets energized or becomes more alert after exercise, it may be best not to exercise in the evening. Regular exercise in the morning even can help relieve insomnia, according to a study.
• Keep your bedroom quiet, dark, and comfortable.
For many people, even the slightest noise or light can disturb sleep like the purring of a cat or the light from your laptop or TV. Use earplugs, window blinds or curtains, and an electric blanket or air conditioner everything possible to create an ideal sleep environment. And don't use the overhead light if you need to get up at night; use a small night-light instead. Ideal room temperatures for sleeping are between 68 and 72 degrees Fahrenheit. Temperatures above 75 or below 54 can disrupt sleep.
• Eat right, sleep tight.
Try not to go to bed hungry, but avoid heavy meals before bedtime. An over-full belly can keep you up. Some foods can help, though. Milk contains tryptophan, which is a sleep-promoting substance. Other foods that may help promote sleep include tuna, halibut, pumpkin, artichokes, avocados, almonds, eggs, bok choy, peaches, walnuts, apricots, oats, asparagus, potatoes, buckwheat, and bananas.
Also, try not to drink fluids after 8 p.m. This can keep you from having to get up to use the bathroom during the night.
• Restrict nicotine.
Having a smoke before bed -- although it feels relaxing actually puts a stimulant into your bloodstream. The effects of nicotine are similar to those of caffeine. Nicotine can keep you up and awaken you at night. It should be avoided particularly near bedtime and if you wake up in the middle of the night.
• Avoid napping.
Napping can only make matters worse if you usually have problems falling asleep. If you do nap, keep it short. A brief 15- to 20-minute snooze about eight hours after you get up in the morning can actually be rejuvenating.
• Keep pets off the bed. Does your pet sleep with you? This, too, may cause you to awaken during the night, either from allergies or pet movements.
Fido and Fluffy might be better off on the floor than on your sheets.
• Avoid watching TV, eating, and discussing emotional issues in bed.
The bed should be used for sleep and sex only. If not, you can end up associating the bed with distracting activities that could make it difficult for you to fall asleep.
Another issue may be sexual dysfunction. Ashton said research suggests it's very common with 31 percent of men and 43 percent of women reporting some degree of difficulty.
For men, the most common sexual problems in men are ejaculation disorders, erectile dysfunction and inhibited sexual desire.
Citing WebMD, Ashton said sexual dysfunction can be a result of a physical or psychological problem:
Some Physical Causes: Many physical and/or medical conditions can cause problems with sexual function. These conditions include diabetes, heart and vascular (blood vessel) disease, neurological disorders, hormonal imbalances, chronic diseases such as kidney or liver failure, and alcoholism and drug abuse. In addition, the side effects of certain medications, including some antidepressant drugs, can affect sexual desire and function.
Psychological Causes: These include work-related stress and anxiety, concern about sexual performance, marital or relationship problems, depression, feelings of guilt, and the effects of a past sexual trauma.
Other causes for sexual problems among men may be a sexual desire disorder, which is an absence of sexual fantasies, thoughts, or behavior, according to WebMD.
Ashton said, "Although this problem is more common in women than in men, about one in seven men reported low libido in a survey published in the Journal of the American Medical Association in 1999. And this figure rises with age."
Erectile dysfunction (ED) may be another culprit. ED is the inability to produce an erection that's sufficient for intercourse. Although this is a relatively uncommon problem for young men, about 44 percent of men ages 40 to 70 have partial or complete erectile dysfunction.
Ejaculatory disorders can also be a problem. Ashton explained these include several orgasmic disorders: Rapid or premature ejaculation occurs when the man ejaculates before penetration, immediately after penetration, or before the couple has achieved a mutually satisfying sexual experience. Delayed ejaculation -- when a man has a normal erection but isn't able to reach orgasm -- is less common, but tends to increase with age.
Certain antidepressant medications, particularly selective serotonin reuptake inhibitors (SSRIs), can cause delayed ejaculation.
For women, sexual desire disorder, the absence of sexual fantasies, thoughts, or behavior, may be at play. Sexual aversion disorder, which is the avoidance of certain types of sexual activity because of anxiety, falls under this heading as well, although it has its roots in different psychological issues.
Sexual arousal disorder may also be an issue for women. This disorder is a lack of sexual excitement, including absence of vaginal lubrication and other physical indications of arousal.
Orgasmic disorder, a difficulty or delay in reaching orgasm, or absence of orgasm after sufficient stimulation, may also be at play.
If you're just looking for more time to fit intimacy into your busy schedule, Ashton suggests considering the time you have sex.
"Nighttime may simply not be the right time for sex for some people," she said. "Change your routine to accommodate meaningful sex and sleep. Try sex in the morning, earlier in the evening, after a nap, or while the kids are at dance or soccer practice. Couples might also try cuddling rather than having intercourse in order to foster closeness and sleepiness, even if one partner is feeling frisky. It is important respect the other's needs and to recognize that intimacy isn't always about sex."
For more on how to get the spark back in your "tired" relationship, go to our partner in health, WebMD.com, and search "Intimacy Tips."