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Moisture wicking robe available in white and light blue with navy tri

Explanations how the MTS fabric used by Cool James for their thermal comfort sleepwear works to keep the user comfortable at night even during the Dog Days. 

  1. Cool Jams helps to get your beauty sleep in the summer heat
  2. Sweating is not bad …
  3. … but the right fabric is a must
  4. How does MTS work?
    • Fast removal of heat and moisture ensures thermal comfort
  5. Cool Jam Inc.’s pieces feel cool at first touch
  6. The comfort of feeling beautiful
  7. Cool comfort is affordable even on a budget
  8. Thermal Comfort Sleepwear in Summary
  9. References


Updated: 1/5/2022

Disclosure: Ad. This post is sponsored by Cool Jams Inc.. The post is not endorsed by them. I wrote the post entirely myself. All thoughts are my 100% honest opinion.


Cool Jams Helps You Get Your Beauty Sleep in Summer Heat

A good night’s sleep is important for everybody’s health. However, many women suffer from waking up at night being bathed in sweat due to menopause as if hot muggy summer nights are not enough already to rob your sleep.


Sweating Is Not Bad …

The human body reacts with perspiration to exercise and/or hot environmental conditions. The sweat evaporates on the skin thereby cooling the body. This genius bio-physical concept works fine when air temperature and relative humidity are in a moderate range. However, evaporation of sweat strongly decreases when the relative humidity in the environment increases. This happens for instance, when a fabric captures moisture and heat between itself and your skin (see schematic view below).  Thus, dressing for the Dog Days is a challenge.


schematic view of fabric not permitting the escape of moisture
Schematic view of the fate of sweat under a fabric that prohibits water vapor transport. Once the thin air layer between the skin and fabric is saturated with water vapor any more sweat cannot evaporate and stays as water on the skin. The wearer feels wet like bathing in warm sweat and wakes up


… But the Right Fabric Is a Must

Scientific research emphasizes that fiber type, yarn properties, fabric structure, finishing, knit structure, and the cut of the clothing affect the thermal-physiological comfort of a person. Such research led to the development of the Moisture Transference System (MST) technology fabric.

woman in button down pjamas from
Button down pajamas with decorative trim made of Moisture Transference System (MST) fabric available in royal blue (as shown here) and black from Cool-Jams


tank top made of fabric with moisture transfer system
PJ combination of tank top with bra and shorts made of MTS fabric. Thanks to the built-in bra the top can double as a tank top on vacation or for exercise. Also available in violet, periwinkle and black


Cool-jams Inc. crafts their sleepwear and bedding using this fabric. This means while you can’t change the weather or switch off hot flashes, you at least can ensure optimal discharge of your body heat, and obtain best evaporation conditions for sweat with the choice of your sleepwear and bedding.


How Does MTS Work?

Fast Removal of Heat and Moisture Ensures Thermal Comfort

For a sense of coolness even on warm or muggy summer nights or during hot flashes, the body heat and evaporated sweat must be able to penetrate thru the fabric to the outside. The lower a fabric’s resistance is to the transport of evaporated sweat the more  comfortable is its sensation.  A low resistance to water vapor transport also ensures that sweat can already evaporate on you skin and provide evaporative cooling.


schematic view of moisture transport thru a fabric
Schematic view of fabric that permits fast water vapor transfer from the inside to the outside. The air layer between the skin and fabric carries less moisture than in the case of a fabric that prohibits moisture transport. Since the water vapor can escape thru the fabric, sweat can evaporate, which leads to the desired cooling.


It is obvious, that water vapor penetrates faster thru a thin than thick fabric. As a consequence, Cool-Jam’s MTS fabrics make use of both aspects. They are thin and permit fast water vapor transport.


Pro tip: Never use fabric softeners on your Cool-Jams Inc. pieces. Recall fabric softeners are designed to cover the fibers. This means that fabric softeners reduce or even clog the fabric pores and hence block water vapor transport.


Pro tip: If by accident a piece got into a wash with fabric softeners, just re-wash the piece again, but without softener. The piece will then perform as effectively as before.


Wicking Provides Additional Benefits for Thermal Comfort

The Cool Jam Ins MTS fabric is also wicking, which means it quickly takes up sweat. Consequently, your body can achieve cooling by further perspiration. In addition, the fabric cools by evaporation of the sweat. These properties provide two benefits: You don’t feel bathed in sweat, and the area for evaporation increases (your skin plus the fabric) thereby providing more cooling. 🙂


schematic view of moisture wicking fabric
Schematic view of a wicking fabric with MTS technology. Sweat evaporates from the skin and cools the body. The resulting water vapor moves thru the fabric. When the fabric gets into contact with the skin, it immediately takes up the sweat. The blue oval represents an area where wicking occurred. The sweat evaporates from the fabric thereby producing evaporative cooling as well.


Cool Jam Inc.’s Pieces Feel Cool at First Touch

Comfort has not only a thermal-physiological, but also psychological and sensorial aspects. The warm-cool feeling of fabrics, i.e. the first sensation, is measured by its thermal absorptivity. When you touch a garment that is at a different temperature than your skin, your skin and the fabric exchange heat. Fabrics with high thermal absorptivity feel cooler at first contact than those with low thermal absorptivity. Smooth fabrics have a large surface area between the fabric and skin, which causes a cool feeling. A large surface area also means an increased area where evaporation may occur.

Cool-Jams Inc.’s sleepwear is made of such fabric that feels soft and cool on your skin. Pulling on a Cool-Jams PJ, for instance, gives you a relaxing feeling of coolness. And who doesn’t love to lay down in a cool-feeling bedding after a long day of hard work?

Stay cool at night in the summer heat with Cool Jams PJ. #health #beauty Click To Tweet


The Comfort of Feeling Beautiful

A psychological aspect of comfort is that you feel beautiful in your clothes. The cut of Cool Jams Inc.’s sleepwear is semi-fitted. It is loose enough to not squeeze, but not too loose that you lay on a mountain of folds. The cuts are classic and the colors are modern – an ageless style.


Who doesn't like to look stylish? Click To Tweet
Cool Jams Inc. baby doll night gown
Moisture wicking baby doll style night gown available in ocean and violet moisture wicking tank top night dress
Chic Cool Jams Inc. tank top cut night dress in MTS technology fabric for a cool comfortable feeling at day and night


Cool-jams’ PJs and night gowns certainly meet the comfort criterion of being well dressed, don’t you think so too?


Cool Comfort Is Affordable Even on a Budget

Cool jams cost about the same as conventional sleepwear. Thus, why not buying cool jams that bring you thermal-physiological, and sensorial comfort in addition to looking great?


Thermal Comfort Sleepwear in Summary

The wicking, wettability and speed of drying properties of the Cool-jam fabric are designed to optimize thermal comfort – a pre-requisite for relaxing sleep.

Give yourself the comfort of coolness at night and/or during exercising and the feeling to look great, start shopping Cool Jams’ thermal comfort sleepwear collection and bedding. You owe yourself a good night rest after a day of work!


When you like the blog, you may also want to get my book How to Dress for Success in MidlifeBuy it now.



Mölders, Nicole, 2019. Outdoor Universal Thermal Comfort Index Climatology for Alaska, Atmosphere and Climate Sciences, DOI: 10.4236/acs.2019.94036

Mölders, N., 2022. Fashion and the Physics of Clothes. Book in Perp.

Oğlakcioğlu, N., Marmarali, A., 2007. Thermal Comfort Properties of Some Knitted Structures. Fibres & Textiles in Eastern Europe, 15, 64 – 65.


Photos of merchandise courtesy to Cool-Jams Inc.

Scientific diagrams: N. Mölders

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