Mailbag - Questions About Sleep

Q. When I wake up in the morning, my t-shirt/sheet/pillowcase is wet from my own sweat. Is it normal to sweat during sleep?

A. Yes, it means your bedroom is warm or you have a lot of coverings on the bed. You probably sweat more in the summer than in the winter. You can reduce or eliminate obvious sweating by reducing the air temperature or sleeping with less bed covering or clothing.

The body’s thermoregulation system during sleep is an interesting topic. The body maintains a tight temperature range through a combination of movement (shivering if necessary) and sweating. Internal temperature doesn’t change much, but it does slowly fall during NREM sleep and rise during REM sleep.

If your body is too warm you will sweat to get that lower temp during NREM, but by the time you wake up your body temperature will increase (you have higher temperature in both REM and waking). That’s why you might sweat during the night but not be actively sweating when you wake up.


Q. Sometimes I become wide awake in the middle of the night. There is no point lying in bed while I am so wide awake, so I get up and do housework. Is this a good idea or should I just tough it out and try to go back to sleep?

A. Sleep experts have started to change their tune in recent years. A period of waking in the middle of the night is now considered ok, and normal for some sleepers. Repeated periods of waking and sleeping are no good, but a single waking period that divides the night into two sleep periods is called a biphasic sleep pattern, and there is evidence many people slept this way before the industrial revolution gave us clocks and electric lighting.

The question is: does this fit with your schedule? Can you modify your schedule to have this hour or so in the middle of the night and still get your sleep in? If you have this hour or so (which is how most people experience it), get out of bed and do something that doesn’t involve exercise. Housework might be ok, as long as it is light. Reading or working on the computer might be better. (Be aware that some people find the light from the computer screen makes it tough to get back to sleep.)


Q. I have too much pain to sleep through the night.

A. Consult a doctor. There are plenty of over-the-counter pain medications that responsible adults can use (follow the directions, especially on dosing.) Some commercially available medications combine an analgesic for pain with an antihistamine to promote sleep. The popular Tylenol Pm is like this. Don’t take these combination medicines unless you need each medicine by itself. If you need a pain reliever AND a sleep aid, fine. But if you need only one of those, there are drugstore products that have only one or the other active ingredients.

More severe pain can be addressed by prescription medication. The opioid class of drugs relieve pain and famously cause sleep. They can be addictive, though, and millions of people have gotten into trouble taking them. Be careful and make sure your doctor knows what you are doing and all other medicines you are taking.

Milder pain in muscles can sometimes be treated by cold packs. This has the added benefit that a cold pack may help you get to sleep faster, especially in the summer.


Q. Does daytime exercise make it harder or easier to get to sleep at night?

A. Both. Exercise is conducive to good overall health – which helps with nighttime sleep onset – and pushes the body to enforce circadian cycles.

The problem with exercise too close to bedtime is that the body may be overwired by the time you are trying to get to sleep. Some people can’t come down fast enough to get to sleep. This is more a problem in the middle-aged and older crowd than for young people and there is considerable variation from person to person. But if you are having trouble getting to sleep, one thing to consider is that you are exercising too late in the evening. Give yourself some time to relax before bed.


Q. My husband/wife/someone in the house snores really loudly. I’m worried about apnea. How can we determine for sure?

A. The definitive diagnosis can be made through the results of a polysomnogram, and this unfortunately is expensive as it involves for an overnight stay at a sleep center. Check with your health insurance about whether they will pay for this type of study. If they will, it is only with authorization and referral from a doctor.


Q. Will certain foods make me dream?

A. No. There is a lot of folk psychology and myths surrounding dreams. Dreams might strike us as weird and ethereal, but they are a normal output of a brain.

Some psychoactive drugs might promote dream activity, and some foods contain caffeine and other substances might, in a small way, increase dream intensity. But we stress “might”. We are unaware of any science showing drugs increase dreaming. When people say they are having a lot of dreams recently, what is happening is that they are rapidly transitioning from REM sleep to waking, so they are more likely to remember the dreams. They aren’t having more dreams; they are remembering them better. We are not aware that any food makes you emerge more quickly from REM.


Q. I want to remember my dreams. Is there something I can do to make that happen?

A. The most memorably, narratively coherent dreams happen during stage R or REM sleep. If a sleeper is awoken suddenly from REM, he or she is conscious of a recent dream about 80% of the time. If you can rig a system whereby you wake abruptly during REM, you can get your wish. However, most people don’t have a home EEG system to determine when household members are in REM. You can set an alarm clock to wake you when you think there is a high probability of REM (REM occurs most often late in the sleep cycle, so you could set the alarm for early morning, maybe a half hour before you usually awaken). This might work for one or two days, but then your body will adjust and you will awaken at that time on your own.

Sometimes you rapidly go from REM to waking without being awoken by external stimuli, and that is conducive to remembering your dreams.



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