Demuestran científicamente que a las mujeres se les enfrían más las manos y los pies después de comer que a los hombres.

Researchers from the University of Granada UGR point out that women have a much more efficient thermoregulatory system than men in response to food.
In the study, published in the journal Clinical Nutrition, 104 men and women participated, whose skin temperature was measured before and after eating.
In a room with the same temperature, they feel colder than men in basal conditions and after a meal.

Why do many women feel cold immediately after finishing a meal, while most men do not? Researchers at the University of Granada (UGR), belonging to the Joint University Institute of Sport and Health (IMUDS), have shown for the first time that this fact has a scientific explanation.

Nowadays it is well known in the scientific literature that eating a meal causes an increase in the energy expenditure of people. At the same time there is an increase in body temperature. thermic effect of food. Most studies to date have focused on studying the increase in energy expenditure and not so much on what happens to body temperature in response to a meal.

In this study of the UGR, published in the journal Clinical Nutrition, A total of 104 (36 men and 68 women) young adults, aged between 18 and 25 years, living in Grenada participated.

All of them came to the research center fasting at 8 am, where a total of 17 skin temperature sensors (called iButtons) were placed on different parts of the body in order to estimate different skin temperature parameters, analyzed with a program developed at the UGR (Temperatus Software: http://profith.ugr.es/temperatus).

Participants lay on a bed for half an hour at rest, at thermoneutral temperature, where their basal metabolic expenditure was estimated by indirect calorimetry. Each participant was then offered an energy shake (50% carbohydrate, 35% fat and 15% protein) individually adjusted to 50% of basal metabolic expenditure.

Thermal sensation

"After ingesting the shake, the participants remained lying on a bed for 3 hours and 20 minutes where they barely moved. Every hour we stopped to ask each participant what their thermal sensation was in different parts of the body," explains the lead author of this study, Borja Martínez Tellez.

In all participants, an increase in mean and proximal skin temperature was observed during the duration of the test. "At the same time, we observed in all subjects that there was peripheral vasoconstriction of the hands during the first hour and subsequently peripheral vasodilation was observed. All these patterns were greater in women than in men, regardless of the body composition of the individuals," explains the UGR researcher.

In other words, women showed a greater increase in mean and proximal temperature and, at the same time, greater vasoconstriction during the first hour and greater vasodilatation during the rest of the hours compared to men.

Cold hands and feet

"At the same time, we also found that women felt colder than men, especially in their hands and feet. Both sexes felt warmer during the test, but women always felt a little colder. It should be noted that the temperature in the room was always the same," said Martínez Tellez.

In light of these results, the UGR researchers point out that, on balance, it appears that women have a much more efficient thermoregulatory system than men in response to food, although they perceive the temperature of a room to be colder than men, even though it is the same.

"In the skin there are a series of neuronal receptors specialized to perceive heat or cold," he points out. Jonatan Ruiz Ruiz, principal investigator of the ACTIBATE project, in which this study is framed, and co-author of the same. "One of the theories that could explain the results of our work is that women have a higher or lower proportion of these neurons compared to men".

Moreover, the thermoregulatory system is mainly orchestrated by the preoptic area (APO) in the hypothalamus and several authors are also suggesting that this possible sexual difference is caused by the size of this area.

Although the strongest theory is that women have fewer vascular plexuses in the hands than men, "and that could be the main explanation for the differences we observed in peripheral vasoconstrictions," the authors note.

On the other hand, it is more widely recognized in the scientific community that women have a more distorted perception of temperature (both hot and cold) than men, and this study confirms these possible sex differences. However, there are several theories that could explain these differences and why women's thermal perception is so far from what has been objectively quantified. Interestingly, this is still unproven, "and there is still a lot of work to be done," they note.

However, the explanation for why many women have to put on a jacket or cover themselves with a blanket after eating is now closer.

Bibliographic reference:

Skin temperature response to a liquid meal intake is different in men than in women

Borja Martinez-Tellez, Lourdes Ortiz-Alvarez, Guillermo Sanchez-Delgado, Huiwen Xu, Francisco M. Acosta, Elisa Merchan-Ramirez, Victoria Muñoz-Hernandez, Wendy D. Martinez-Avila, Miguel A. Contreras-Gomez, Angel Gil, Idoia Labayen, Jonatan R.Ruiz

Clinical Nutrition

Available online 2 June 2018

https://www.sciencedirect.com/science/article/pii/S0261561418302127

Images attached:

Image of where the skin devices (iButtons) were placed.

The shake taken by the subjects who participated in the study.

Image of a participant during one of the tests.

Part of the UGR researchers who carried out this study. From left to right, Elisa Merchán Ramirez, Borja Martínez Téllez, Jonatan Ruiz Ruiz, Huiwen Xu, Guillermo Sanchez Delgado, Lourdes Ortiz Álvarez and Francisco Miguel Acosta Manzano.