Snow free plus somewhat degree and no cold wind at your place? Congratulations you are lucky. But most are freezing in the current or upcoming cold winter times. And even if you plan to stay home and hold winter sleep – the day will come were your notice that you are not a bear, the fridge is empty, or friends will succeed in asking you for going out. For those going out without any heater available, I would suggest you some physical and tangible (and cheap) heater, the person around you, to warm your hands.
I will introduce you where to touch according to body temperature distribution and some elements which can have an impact on it such as genders, moods, figures and so forth. Or in other words: How to make the best use of your partners (otherwise wasted) heat. Some science for you:
The Science
Human body temperature contains the temperature of the core and skin. Core temperature refers to the temperatures of abdominal, thoracic and cranial cavities, with a slight difference in different parts, whereas the skin temperature refers to the temperatures of the skin and subcutaneous tissues. Regulated by the brain, the core temperature is normally stable, and higher than the skin temperature, which is more affected by skin blood flow and environmental conditions.
However, the physiological definitions for the temperatures of skin and core are not constant all the time, due to the relative change of “skin” and “core” parts in various environmental temperatures. In cold condition, the area of the core temperatures shrinks to mainly head and trunk, while in warmer condition, it can extend to limbs. The core temperature is related to skin temperature to some extent, but since getting the warm organs from your partner is pricy, the skin temperature would be paid more attention to.
In total, the skin temperature changes in a gradient from the head and trunk to the limbs. For both men and women, the temperatures of head and trunk are relatively higher than that of limbs. The skin temperature distribution of a male and a female is illustrated in Figure 1. The reaction of the skin to surface cooling is primarily manifested as a local vasoconstriction and reduced blood flow. Reduced skin blood flow slows down the heat transfer between the body core and the environment significantly even with a mild cooling. The body core remains stably warm while the skin temperature can drop considerably when it gets colder further.
Figure1. Infrared thermal images of the anterior body for a male (upper side) and a female athlete.
Source: Tanda, 2015
Body composition can influence heat loss and skin temperature. It has been shown that increased body fat percentage is related to decreased skin temperature while it tends to increase the hand skin temperature. In another word, obese people tend to have lower body temperature except hands. This can also explain women have lower body temperature, with the related to body fat percentage. However, facial skin temperature has not been found related to body composition.
Your advantage
But good news for everyone with a ‘cold’ partner: You can heat him/her up! Emotions influence our temperature (everyone who visited the school and remembers the sweaty hands after being called to the blackboard knows). So make use of that!
Emotions can lead to changes in the skin temperature, as they have an impact on regional skin blood flow, which plays a vital role in the skin temperature. Researchers investigated the body temperature change affected by different moods such as love, disgust, anger, pride, etc. Emotions related skin temperature distribution is shown in Figure 2. The study showed emotions like fear and anxiety activated the upper body except the arms. Sadness cooled down limbs, while love and happiness warmed up almost the whole body. Which means, do something to activate the emotions of your partner, in a positive or negative way, to have warm regions as you like. We recommend triggering positive emotions for keeping your warming source longer.
Figure 2. Bodily maps of emotions.
Source: Nummenmaa et al., 2013
Although we have our sophisticated body temperature regulations to protect us from the cold weather, life would be much harder without efficient clothing. In my practice, the warmest area could be found on the hooded area on the upper back of a hoody or under the dressed arm—where is totally blocked from any heat transfer with the wind and coldness.
Alternatively, make your partner happy and loving you – in return his/her body will warm up and you can participate from it by getting warmed and cuddled. For those without a partner or a friend willing to cuddle in public we recommend Japanese heat-plasters or to endure the cold and reward yourself with a hot shower at home. For all bears reading this text in spring: Yes, you are lucky.
Publication bibliography
Abramovits, William; Graham, Gloria; Har-Shai, Yaron; Strumia, Renata (Eds.) (2016): Dermatological Cryosurgery and Cryotherapy. London: Springer London.
Chudecka, Monika; Lubkowska, Anna; Kempińska-Podhorodecka, Agnieszka (2014): Body surface temperature distribution in relation to body composition in obese women. In Journal of thermal biology 43, pp. 1–6. DOI: 10.1016/j.jtherbio.2014.03.001.
Diller, Kenneth R.; Khoshnevis, Sepideh; Brothers, Matthew (2016): Effects of Cold Temperature on the Skin. In William Abramovits, Gloria Graham, Yaron Har-Shai, Renata Strumia (Eds.): Dermatological Cryosurgery and Cryotherapy. London: Springer London, pp. 39–43.
Drummond, P. D.; Quah, S. H. (2001): The effect of expressing anger on cardiovascular reactivity and facial blood flow in Chinese and Caucasians. In Psychophysiology 38 (2), pp. 190–196.
Katić, Katarina; Li, Rongling; Kingma, Boris; Zeiler, Wim (2017): Modelling hand skin temperature in relation to body composition. In Journal of thermal biology 69, pp. 139–148. DOI: 10.1016/j.jtherbio.2017.07.003.
Neves, Eduardo Borba; Salamunes, Ana Carla Chierighini; Oliveira, Rafael Melo de; Stadnik, Adriana Maria Wan (2017): Effect of body fat and gender on body temperature distribution. In Journal of thermal biology 70 (Pt B), pp. 1–8. DOI: 10.1016/j.jtherbio.2017.10.017.
Nummenmaa, Lauri; Glerean, Enrico; Hari, Riitta; Hietanen, Jari K. (2014): Bodily maps of emotions. In Proceedings of the National Academy of Sciences of the United States of America 111 (2), pp. 646–651. DOI: 10.1073/pnas.1321664111.
Salamunes, Ana Carla Chierighini; Stadnik, Adriana Maria Wan; Neves, Eduardo Borba (2017): The effect of body fat percentage and body fat distribution on skin surface temperature with infrared thermography. In Journal of thermal biology 66, pp. 1–9. DOI: 10.1016/j.jtherbio.2017.03.006.
Tanda, G. (2015): The use of infrared thermography to detect the skin temperature response to physical activity. In J. Phys.: Conf. Ser. 655, p. 12062. DOI: 10.1088/1742-6596/655/1/012062.
遊俠 (2007): 人體體溫熱分布圖. Available online at https://tw.answers.yahoo.com/question/index?qid=20071102000015KK08317, checked on 12/31/2017.