Yes, Men and Women are different … when it comes to how they handle the heat.

Women and Heat Stress: Physiological Differences and What They Mean for Cooling Product Design

Heat stress affects everyone differently.  Unfortunately, most of the historical studies regarding the impact of heat on humans focused on males, though this is changing.  And shock upon shock, as more studies are conducted focusing on how females handle the heat, we are finding that there are differences.  These differences will impact personal cooling garment designs, but before tailoring these garments for women we need to better understand how female bodies handle and react to heat differently.  The one size fits all model does not work for heat stress management #coolingsolutions.

So what is the science saying so far?  Women Thermoregulate differently to men, but not necessarily less effectively!  As I try to delve into some of the details on this, I will try to provide what I hope is a simple and clear overview of the science.  My main focus will be on how these findings need to force a change in how we design our cooling garments.  Some of the results of the research I have read so far have surprised me.  Some of the lack of certainty or clarity did as well.

So some highlights of some research I did regarding how men and women handle the heat differently.

• Women generally have a higher body surface area-to-mass ratio (they have more skin surface area relative to their total weight compared to men). Because skin surface is the primary site for heat dissipation, this ratio affects thermoregulation, often allowing for more efficient heat loss but also faster heat gain in hot environments.  Now consider that with the below point.

• Now this is a kewl finding I never considered before.  Studies are indicating that women sweat less and manage body temperature more through blood circulation than sweating, so they can handle hot/humid environments better.  Men sweat more so they can handle hot/dry environments better.  Women generally have a higher surface area-to-mass ratio, which helps them dissipate heat more effectively in hot-humid environments through blood circulation. In contrast, men's higher sweating capacity makes them more efficient at cooling down in hot-dry conditions where sweat evaporates quickly.

• Of course there is the hormonal influence women have to deal with when managing the heat.  Hormonal fluctuations (menstrual cycle, menopause & hot flashes) affect thermoregulation significantly and not for the better.

• Pregnancy and the associated hormonal fluctuations is another factor to consider when evaluating women and how they manage the heat

• Women begin sweating at a higher core temperature and sweat less overall in different areas than men

These points make it clear that women need different considerations in the design of their cooling gear.  One size fits all in PPE and life does not work.  You also have to consider the best cooling technology to use.  Active cooling with PCM and/or KewlFabric 7101, or passive cooling solutions with high end wicking and evaporating fabrics that rely on sweat for evaporative cooling.

For more details, this report from the American Physiological Society made for some very good reading.

Considering some of the key points regarding the differences between how men and women handle the heat mentioned, we need to look at the cooling technology used, and designs needed to create the most effective cooling solutions for women.

Key Design Considerations

A. Women tend to have lower sweat rates but higher skin blood flow as a cooling mechanism so they can handle hot/humid environments better.  Men sweat more so they handle hot/dry environments better.

B. Women begin sweating at a higher core temperature and sweat less overall in different areas than men.

C. Women have a greater variety of “heat” scenarios caused by hormonal fluctuations. Women may not just be battling the environmental heat, they could be battling heat caused by hormonal fluctuations.

When developing a cooling solution for women, we have 3 main options to consider

1. #KewlFabric 7101 and its ability to absorb and hold extra water and slowly evaporate it thereby supercharging your bodies natural cooling process.  Ideal for dry climates with airflow.

2. #PhaseChangeMaterial that absorbs heat away from the body to keep you cool at a fixed temperature.  Ideal for high humidity climates or climates with no airflow.

3. High end wicking (take sweat off the skin) and evaporating (speed up the evaporation of sweat/liquid)) fabrics.

Considering A & B above, a garment made using KewlFabric 7101 (#1 above) in conjunction with a high end evaporating fabric (#3 above) would help increase cooling through evaporation for women and would be a low cost option in dry hot environments.  The flexible design options with KewlFabric 7101 would also make it easy to design garments with cooling zones in places ideal for women such as the chest, neck and lower back. High end wicking and evaporating fabrics alone would not be the ideal solution for women because they rely on sweat to work.

Phase Change Material as a cooling option would work in hot and dry climates, with or without airflow, and in high humidity environments.  The right design using PCM would address A, B and C above.  Regarding C above, PCM should be a good option for providing targeted, consistent cooling.

Designing cooling solutions to address the different needs of men and women requires that you have the skills and the right cooling technologies best suited to meet the different needs of each party.  There is no “one size fits all” when it comes to the right personal cooling solution.

The Technology of Kewl! Beat The Heat! Get It Done!