Every summer, the issue of air conditioning in trains and whether they are too hot or too cold comes up. While the various train operators in Tokyo make efforts to keep passengers comfortable, they still receive complaints from both people who find it too hot and people who find it too cold. The Mainichi Shimbun looked into the issue, and provides tips for people who are on the cold-sensitive side of the spectrum.
Train operators other than JR in the metropolitan area run their regular cars at a set temperature of 26 degrees Celsius, and their lightly air conditioned cars at 28 degrees Celsius. This is not the result of an agreement between the companies, but, according to Seibu Railway Co., it is "the result of our own decision after hearing the opinions and requests from passengers." With train lines run by different companies increasingly being directly connected to each other in the metropolitan area, it is likely that having the same temperature settings is also more convenient.
East Japan Railway Co. (JR East) uses different temperature settings on its different lines, but like the other companies sets its lightly air conditioned cars 2 degrees higher.
When Tokyo Metro Co. set all of its train cars' air conditioning at 28 degrees in late April 2011 after the Great East Japan Earthquake in order to save electricity, it was inundated with complaints that the cars were too hot, and in July that year it returned the cars to their normal settings.
A press relations spokesperson for Tokyo Metro said, "It is difficult to save energy through just air conditioning adjustments. Through measures such as adopting LED bulbs and improving the performance of control devices, we are aiming for large-scale energy savings across the train cars as a whole, while also providing a comfortable interior environment."
Most train cars being operated in Japan today use computer-regulated air conditioning, and some of the newest cars can make frequent, fine adjustments. Odakyu Electric Railway Co. uses air springs under the floor to detect boarding and alighting from the train, and the air conditioning is automatically adjusted when the cars are detected as crowded to better circulate air and eliminate uneven humidity in the cars. JR East uses a system that predicts the passenger load at stations based on previous data and cools the cars ahead of time when a train is approaching a station predicted to have a heavy passenger load. Seibu Railway Co. uses heat reflecting glass in its passenger car windows and makes the air conditioning system more effective.
However, a representative for Odakyu Electric Railway Co.'s corporate social responsibility and public relations section says, "The temperature that passengers feel is affected by things like the outside temperature and the sunlight coming in through the windows. Regardless of the season, we receive both opinions that our cars are too hot and that they are too cold."
It seems that most of those who complain that train cars are too cold are women, and that most who feel that it is too hot are men. Associate professor of hormonal studies Miyuki Katai of Tokyo Women's Medical University Medical Center East's gender-based treatment section says, "While it depends on the individual, lots of data shows that when clothed, men and women feel a difference of about 3 degrees Celsius in the temperature."
Muscles are used to produce heat in the body. People shiver when they are cold because, Katai says, "Muscle tissue naturally shrinks and starts moving in order to create heat." Since women usually have less muscle then men, they produce less heat this way and are more likely to feel cold. Body fat, meanwhile, is used to store heat, but if it is cooled, it tends to take some time to warm up again. Women tend to have more fat, which is another reason they are more likely to feel cold.
Furthermore, there is an increase among young women in cases of being underweight, or having a body mass index of less than 18.5, in which case there is little muscle or fat. This limits their ability to create or store heat, and makes it more likely they will complain of being cold.
In addition to physical differences between men and women, clothing differences cannot be ignored, either. While so-called "Cool Biz" light summer business attire has gained ground, many men still wear shirts closed around the neck or suit jackets while in the train. Women, who are more likely to wear lighter clothing that is open around the neck have their skin directly exposed to the flow of cool air from fans in the train car ceiling.
Since people cannot suddenly make a large boost to their muscle or fat, the way to better create internal heat is through eating. Katai recommends, "It's especially important to take in carbohydrates. You should eat breakfast, even if it is just one rice ball. Without breakfast your body cannot make heat and you are more vulnerable to the cold."
While on the train, she recommends, "Wrap a stole or similar item around your neck to block the cool air coming from above. For clothing with a design that permits air flow from the neck down to the bottom of the fabric like a one-piece dress or a tunic blouse, just wearing a belt should change the temperature you feel."