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Why Night Sweats Occur and How to Stop Them

Posted Apr 26 2010 6:29pm

In order to stop night sweats naturally you should learn about the mechanics of sweating. There is no reason why you should suffer from night sweats ever again. Once you understand how sweating evolves, you will have the knowledge to make night sweats stop.

Your Body Uses The Following Methods To Keep Itself Cool:

* Radiation (radiant energy)

* Conduction (conductive heat transfer)

* Convection (conveyance of heat)

* Sweating (we are trying to avoid this)

Our body cools itself by four main methods. The first method is radiation. Radiation is like the heat that you feel while standing in front of an oven that is on.

The second method is conduction. Conduction is the heat that you feel if you touch the oven while it is on. The third method is called convection. Convection is heat that is picked-up by the air that passes by the oven while it is on.

Simply put, convection is heat that is conveyed to the air surrounding the hot object. The forth and final method of cooling is evaporation, better known as sweating.

Typically body cooling takes place in that very order. If the body will not cool itself via radiation, conduction, or convection, you will start to sweat.

The Temperature Pendulum

The objective here is to teach you how keep your body cool and keep from sweating at night. To fully understand how to manage night sweats you must understand each method of cooling your body in order to fully evaluate your options.

One thing you should make note of is that your body will normally maintain a relatively constant temperature throughout the night. The problem occurs when your body is not keeping a constant temperature during the day or night.

People that suffer from night sweats understand the concept of varying body temperature. Therefore you will look at the cooling cycle with that in mind.

A Balancing Act

The temperature balancing act starts when you get in bed at night. You feel the cool of the sheets and the comfort of the bed. This is a good example of conductive heat transfer. Whenever there is a difference in temperature between the object you are touching and your body, you will feel either a warming sensation or a cooling sensation.

Remember that heat travels from hot objects to cooler objects. So if you touch ice you feel cold because the heat is leaving your body and going into the ice.

If you touch something that is warmer than your body you feel warmer because heat is moving from the hot object into your body. That is conductive heat transfer.

Now what happens when you are next to an object long enough to equalize the temperatures? Let’s go back to the bed scenario. When you get in bed it feels cool. Right away your bed starts to absorb the heat your body is generating.

The problem arises when the material that is absorbing your body heat is no longer able to absorb more heat. At that point your body starts to look for other methods of cooling.

In Your Bed

Heat transference by radiation will be absorbed by your bed. Radiant energy will be absorbed by the bed material until you reach a point at which the bed can no longer absorb more radiant heat.

Conductive heat transference, which is the heat that is transferred when you touch something, will be absorbed into your bed as well. This heat will also accumulate until your bed can no longer absorb any more.

Convection, which is the transference of heat by conveying that heat, in this case to air, is only effective when you can generate air movement within that space. Heat will transfer from your body to the air around you and then move off, either by a buoyancy difference or by induced movement.

What this means is that when air gets warmer it tends to rise and be replaced by cooler air. If the air is induced to move, like standing in a breezeway or next to a fan, hot air will move off giving fresh cooler air an opportunity to absorb more heat.

Being that you are in a bed, covered with sheets, and the air surrounding you is trapped, the fresh air required for convection to work properly, is not there.

But if that was case wouldn’t everyone sweat in bed? The short answer is no.


There is a point where you reach equilibrium between heat absorption of your bed and heat generation of your body. This is the point where your bed is able to absorb enough heat to keep you comfortable. This is your comfort zone.

Let’s say your body generates 200 units of heat every minute. Now equilibrium is where the bed is able to absorb 200 units of heat each minute. At that point you can sleep comfortably; you are in an equalized state.

Now let’s say your bed is absorbing 250 units of heat every minute, but you are only generating 200 units of heat each minute. In this situation you will have a cold bed. This is not equilibrium.

If your bed can only absorb 150 units of heat each minute and you are generating 200 units of heat, then you have a hot bed. This again is not equilibrium.

Those Hot Bodies

If you are suffering from night sweats, your body is generating heat at different levels during the night. Although you are able to get into bed and it feels nice and cool, that feeling fast evades you. For those of us that have night sweats, we are dealing with a body that generates heat at varying temperatures all night long.

As with the previous mentioned equalized bed scenario, when you first get into bed your body is generating 200 units of heat each minute. Your bed is absorbing 200 units of heat each minute. You are in equilibrium, all is well. But then your body temperature rises.

Now your body is generating more than 200 units of heat each minute and your bed can’t keep up. If you are generating 250 units of heat each minute and the bed can only absorb 200 units of heat, where will those extra 50 units of heat go? They will go nowhere. They start to accumulate and buildup between the sheets.

This buildup of extra heat starts a downhill roll right to sweating. Once the extra heat starts to accumulate, and your body starts to get warmer, the only method left for cooling your body is sweating.

Turning Off The Oven

So the question is how do you solve the problem of excessive heat that leads to sweating. In order to do this you must look at the three main methods of cooling and see what you can work with to keep your body cool.

Radiation is the first method used by your body to eliminate heat. Yet that heat is much like heat transferred by conduction. It is absorbed into the bed and will contribute to night sweats. This heat must be drawn out of your bed.

Conduction is the second method of cooling your body. The only way to utilize this is to make the bed much cooler. Conduction is the method that doctors are prescribing when they tell you to keep your room cooler.

Keeping your room cooler will help your bed absorb more radiant heat and conductive heat but relying on conduction can be cumbersome. The cost associated with hyper cooling a room and the effect extra coolness has on other members of the house are just two reasons to look else ware.

Remember the bed that absorbs 250 units of heat is a cold bed when you are only generating 200 units of heat.

The third method of keeping you body cool is to utilize convection. But convection requires air movement to be effective. So how do you move air when you are between the sheets?

There are several things you can do move the air between your sheets. One is to kick off the covers and let some cool air in. The other is to raise the sheets and allow some air to flow in. When you lower the sheets the hot air flows out, The other option is to use a fan made specifically for this situation.

Keeping Your Cool

With all the methods stated above you will find that moving air between your sheets and around your body is actually a simple, cost effective way to keep your body and your bed, cool.

A special fan that can generate a light breeze between your sheets will be more effective then lowering your thermostat by six to eight degrees. This type of cooling system will also benefit you in the following ways.

* Much lower cost of cooling then air conditioning.

* Variable speed under your pillow

* Can be directed at a single user

* Evacuates stagnant, humid air trapped between your sheets

* Keeps you and your bed at a constant temperature

A system like this will generate a light breeze that will travel between your sheets along your body and push the hot air out of your bed. It will also eliminate the heat that has been building-up within your bed.

Any conductive heat or radiant heat that has built-up in your bed will be eliminated with the breeze. Neither your body nor your bed will accumulate that extra that typically awakens you at night. .

The extra body heat that you generate during the night, will be quickly moved out from between your sheets. This simple breeze will keep your body from ever reaching the point at which it starts to sweat. This is the most effective method of dealing with night sweats when you look at it from a thermal dynamics point of view.

There are other methods of dealing with the effects of night sweats, like wicking pajamas and absorbent sheets, but those are not dealing with the problem at hand. They are only dealing with the aftermath of the problem. They are collecting sweat. What you want to do is keep from sweating all together.

Kurt Tompkins is the inventor, developer and manufacture of the Bedfan personal cooling system. A product designed strictly out of necessity and made with simplicity in mind. The Bedfan cooling system let us show you how

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