Summer is here. Even in London the temperature hit 36℃ one day, which was a record high in the last 10 years. It makes you want to reach something cold like ice cream, cold drinks & juices, and chilled foods. If this continues for weeks and months, you may develop a condition called Summer Heat Weariness or “Natsu Bate” in Japanese.
Before refrigerators and air conditioners, Natsu Bate used to imply “losing body weight due to summer heat”. That was because in the summer, foods went bad more quickly without refrigeration; the working environment was poor without air conditioning, and energy consumption went up due to raised metabolic rate with the heat. So people developed summer heat weariness or Natsu Bate and lost some body weights.
Modern Natsu Bate, however, seems to have presented us with a quite different picture, possibly like this. When it gets hot, you tend to go for something sweet and cold, like chilled fruit juice, which does not require intestinal digestive activities. Because it is hot, you seek for air-conditioned rooms, but obviously have to go back and forth between these cool rooms and outdoor hot spaces quite a few times a day. Our body’s autonomic nervous system is forced to make adjustments of its functions according to the temperature changes all throughout the day. Making excessive adjustments is a great stress for the autonomic nervous system.
Here is an interesting experiment that Dr. Tei (2011) conducted (p71). A mouse was made to travel between a refrigerator and a room with a room temperature 5 times a day. The finding was that the most damaged part of the body was the mouse’s intestines. The mucous membrane of the intestines got thinner, and undigested foods were found in the mouse’s faces. This suggests that the great stress is placed on the intestines with just five trips a day between the hot and cold places for the mice and therefore, you need to take a good care of the intestines even more in the summer.
If we repeat with Hot & Cold environments, internal Cold (from cold drinks & foods) and excessive amount of sugar intake, not only the autonomic nervous system weakens further; but also our digestion and/or whole body goes out of balance. This leads to weariness, poor appetite, but also possible weight gain. If your body weight goes up by 2 ~ 3 kg a day, often the water metabolism is not working well and it leaves you with bloatedness, swelling and/or a heavy feeling. This is modern Natsu Bate, and far from losing weight.
Furthermore, because of the “Cold” in our body although it is hot outside, women may experience irregular menstrual cycles and/or menstrual disturbances. Kampo doctors say that women’s abdomen and lower back at around the navel level should be warm for good female health. Others may experience an inability to focus on things, and could catch colds more easily in the summer, and other conditions associated with lowered immunity. You become weak, but the body weight goes up – this seems to be a classic modern Natsu Bate.
The way to sail through the hot summer and stay away from modern Natsu Bate is avoiding cold drinks & foods and sweet drinks & foods as much as you can. Needless to say, hydration is important. Why not try hot herbal teas and water at a room temperature. They would be kinder to your body. Cooked foods are better than chilled foods for the intestines too.
Enjoy your summer!