Melatonin and Sunlight

If you were to ask several people why they think we sleep, you would probably get as many answers as the number of people you asked. Some people might say that we sleep because of a comfortable bed and quiet surroundings. Other common answers would include exhaustion, a full stomach, or because we have someone to snuggle with. Very few people actually know the correct answer to that question. What makes us sleep is the release of a chemical called melatonin.

Melatonin is a hormone that the brain produces. It is secreted by the pineal gland, which is located at the base of the brain. This chemical is what maintains the body's sleep-wake cycle and it is released at various times during each day. The pineal gland is responsible for the release of several different hormones that regulate many of the body's functions, including the internal clocks.

Melatonin is closely related to the body's temperature, and they are both controlled by something called the circadian rhythm. Both body temperature and levels of melatonin will increase as the day moves on toward night. Each of these will be at their highest levels of the day when you are asleep at night.

Melatonin levels remain low during the day because the pineal gland that releases the chemical is triggered by darkness. More melatonin enters the bloodstream when it's dark, as opposed to the minute traces of it during the day. The melatonin in the bloodstream is what makes the body begin to get tired. The more melatonin there is, the more tired you will become. As you begin to fall asleep, your blood pressure will slow as well. This increase of melatonin will continue until around 3 or 4 a.m., at which point it will begin to decrease. This means your body is preparing itself to wake up.

If the release of melatonin is somehow interrupted, the sleep cycle will be as well. Lower melatonin levels will fool the body into thinking it is time to be awake and alert. Your body can be made to think it is time to go to sleep any time there is extended periods of darkness. This will again trigger the release of melatonin into the bloodstream.

The production of melatonin can be affected by the weather as well. This is especially true during the winter months when the days are shorter and do not have as many hours of sunlight. You may also experience increased levels of melatonin if you work in a poorly lit office. People in this situation will often feel tired and less energetic due to the body thinking it is supposed to be falling asleep. This type of lifestyle can cause an imbalance because when more melatonin is released during the day, there will be less production at night. This is the reason for many of the sleeping disorders that many people suffer from, including insomnia.

When there is a shortage of natural light, light therapy can help. Allowing your skin to receive the proper amounts of natural sunlight is the most effective way to maintain proper levels of melatonin.

         

Intro to Sleeping Well

Different Stages of Sleep Cycle
Circadian Rhythm and Sleep
How Much Sleep Do We Need