The real reason you and your spouse fight over the blanket and air-con remote control

Dr Ben Ng, an endocrinologist from Mount Elizabeth Novena Hospital, noted in the study that “women tend to express more dissatisfaction with temperature deviations”. 

“Women tend to prefer a more specific temperature, and can sense small changes and get more uncomfortable when the temperature changes, particularly in cold weather. Men tend to be less affected by temperature changes.”

This difference in temperature perception can be caused, in part, by “their different body compositions,” said Dr Tey Hong Liang, senior consultant and head of the National Skin Centre’s Research Division. “Women generally have a higher percentage of body fat versus muscle mass, while men have a higher percentage of muscle mass versus body fat.”

As a result of having more muscle mass than women, men generally have a higher basal metabolic rate and produce more heat.

As a result of having more muscle mass than women, men generally have a higher basal metabolic rate and produce more heat, said Dr Tey, who is also assistant professor at the Lee Kong Chian School of Medicine. This may explain why men need a cooler ambient temperature than women to stay comfortable.

WHAT HAPPENS WHEN YOU FEEL COLD OR WARM

Regardless of muscle mass and body fat percentage, both genders need to maintain a core temperature that allows for the body’s functions to hum along nicely – between 36.1 degrees Celsius and 37.2 degrees Celsius, according to Dr Ng. And this temperature range is regulated very tightly by the hypothalamus in the brain.

Like a command centre, the hypothalamus receives signals from the environment through specialised nerves called thermoreceptors, and signals accordingly to the body to increase or lose heat to keep the body temperature stable, said Dr Ng. This is known as the hypothalamic set point of the body. 

If things are heating up, the hypothalamus triggers the sweat glands into pumping out perspiration to cool things down. At the same time, the blood vessels dilate to send warm blood closer to the skin to cool off.  

Feeling cold? Your blood vessels take on the opposite action by constricting. When this isn’t sufficient to keep the warmth in, the hypothalamus has another trick up its sleeve: Your muscles start to contract, causing you to shiver.

Most of the heat in the body is produced by deep organs such as the liver, brain and heart.

According to Gordon Giesbrecht, a professor of thermophysiology at the University of Manitoba in Canada, you could produce from 100 watts, up to 600 watts (in cases of mild hypothermia) of heat by shivering.

Your skin has the highest number of thermoreceptors as it is the outermost organ. Interestingly, the organs that generate the most heat are also equipped with thermoreceptors to detect and dissipate heat, said Dr Tey. “Most of the heat in the body is produced by deep organs such as the liver, brain and heart. The other major heat source are the muscles during exercise.”

WHAT CAN ‘ADJUST’ YOUR INTERNAL THERMOSTAT

There are factors that can disrupt your hypothalamic set point and affect how you perceive temperature. “An increase in weight with an increase in fat content can reduce the amount of heat loss,” said Dr Tey. “Conversely, an increase in muscle content would increase the amount of heat production.”

Women’s hormonal change is another variable in the equation. “Hormonal changes in women, such as menstruation and pregnancy, can affect their core temperature and temperature perception, and also affect their metabolic rate,” said Dr Ng.

Where you live geographically is another factor that affects how you perceive heat, said Dr Tey. “A person staying near the equator will have more efficient mechanisms for heat loss, and therefore, perceive heat differently from someone staying in a cold climate.”

Of course, your body acclimatises with time and that is why the longer your winter holiday is, the better you are at coping with the cold. Similarly, even a person exposed to heat several hours a day while performing a reasonably heavy workload will develop increased tolerance to hot and humid conditions within one to three weeks, he said.

A person exposed to heat several hours a day while performing a reasonably heavy workload will develop increased tolerance to hot and humid conditions within one to three weeks.

HE’S SWEATING BUT SHE’S FREEZING

How does your hypothalamic set point come into play in real life? Here’s a look at how your body’s perception of temperature can lead to interesting work and domestic situations with the opposite sex.

• IN THE OFFICE

If women typically have a higher body fat percentage, why do they feel cold quicker and more often than men in the office? Doesn’t fat insulate you against heat loss? “Fat is indeed a good insulator as it only conducts heat one third as readily as other tissues. However, the heat production in women is lower due to a lesser amount of muscle,” said Dr Tey. “Although the rate of heat loss is slower in females, the total amount of heat lost in a similar-sized female and male is similar.”

Compared to her male colleagues, a woman doesn’t produce enough heat to make up for the amount she loses. This may explain why she may feel the need to reach for the cardigan more than men when exposed to the same office for a prolonged period.

Women are also more likely to have cold fingers and toes in chilly places. This happens because the fat surrounding the vital organs can restrict blood flow to the extremities – and women do have more fat than men.

Cold fingers may also let women “perceive the temperature as too low due to the thermoreceptors sensing inadequate blood floor and lower temperatures,” said Dr Ng.

But if human physiology is not the reason for the faux winter situation in the office, it is a good idea to check with building management that the indoor temperature is between 22.5 degrees Celsius and 25.5 degrees Celsius.

Point the building management team to the NEA’s Energy Efficiency Improvement Assistance Scheme, which subsidises up to 50 per cent of the cost of engaging an energy services company to audit the building’s energy consumption and improve energy efficiency. 

• IN THE BEDROOM

Why does he find the air-conditioning not cold enough, while she is hogging the duvet the minute she gets into bed? Dr Tey’s take is, women start off with a lower rate of heat production and lower net amount of heat, so they feel cold more often.

“Although women have a higher fat percentage and more insulation, they tend to have a greater surface area, too,” said Dr Ng. “There is more exposed skin, and hence, women can be more prone to heat loss through the skin.” Women’s diet, which is often lower in refined sugars, and smaller in proportion than men’s, can also affect heat perception, he added.

But why do men end up needing the blanket, too? “The core body temperature in men and women both drop by one to two degrees Celsius when the metabolism starts to fall during sleep,” said Dr Ng.

According to Tan Tock Seng Hospital’s website, the body temperature hits its lows between 3am and 6am for both genders – causing men to start their mid-sleep search for the blanket, which by then, is already wrapped around her like a tightly rolled popiah skin.

• IN THE SHOWER

Women typically can withstand a higher water temperature than men, and you’d know from the near-sauna conditions that a female member of the family has just taken a shower. 

A possible explanation is that men generally have a higher basal heat production than women, said Dr Tey. “This results in men’s need to lose more body heat to maintain the same hypothalamic set point as females.”

A happy shower temperature for everyone at home is between 36 degrees Celsius and 40 degrees Celsius, said Dr Tey.