What environmental factors can affect sleep?

What environmental factors can affect sleep?

The most important factor is the temperature. The brain acts slowly if its temperature is in a comfortable zone. Temperature controls the brain activity and in turn; the body activity. If it is cool it affects the brain to be in rest and one can sleep. Another factor is light - we need darkness or toned light - the mixture of dark and light. The third factor is sound. When we close our eyes we feel comfortable, but if sound is there our eyes will open so we need a quiet environment. The other factor is the surface of the mattress. The smoother the surface; the better we will sleep.