Write an article based on this summary:

Elevate your head with pillows. Sleep with pillows under your knees. Ensure your mattress is comfortable and supportive. Invest in a humidifier.
Using one to two pillows to raise your head four inches will make it easier for you to breathe as you sleep. You may also want to consider buying pillows that are specially designed to keep your neck muscles relaxed and open, allowing you to get a more comfortable sleep.  Sleeping with your head elevated can be especially helpful for those who have sleep apnea or acid reflux. You may need to try sleeping on one to two pillows for a few nights to determine how many pillows you require to be comfortable when sleeping at night. You may want to consider orthopedic pillows that conform to your neck and head and provide good support as you sleep. Wedge-shaped foam pillows can also support your head and help you breathe properly when you sleep on your back. Sleeping on your back can put stress on your spine and your lower back. Place one to two pillows under your knees before you go to bed so that your spine is properly supported and there is less stress placed on your lower back. When you are sleeping on your back, it is essential that your mattress provides good full-body support, including lower back support. In a mattress, support is provided through the coils or inner springs. Different mattresses will have different arrangements and numbers of coils. As well, the padding of the mattress can come in different thicknesses, from seven to 18 inches deep. You should always try a mattress before buying it to ensure it is comfortable and supportive for your body.  Often, a medium firm mattress is more comfortable as it allows your shoulders and hips to sink in slightly. If you have lower back pain, you may want to consider a firmer mattress with a padded cover for support. Check your existing mattress to make sure it does not sag at all or cause you any discomfort. If so, it may be time to invest in a new mattress. Though you can use boards underneath the mattress to help with the sagging, this is a temporary fix and you will eventually need to buy a new mattress to get a good night's sleep. Dry air can irritate your nose and throat and lead to congestion and snoring at night. To keep the sleeping environment comfortable and moist, sleep with a humidifier on. You can find humidifiers at your local hardware store.