Editor's note

The ancient Chinese created an agricultural solar system - still in use today - that is based upon their observation of crops, climate, astrology, and the study of animal and plant life cycles. The system guided farmers as to when to sow seeds and when to harvest them, and this system has now been in place for more than 2,000 years.

Today, with advances in science and technology, agriculture depends less on this ancient wisdom. But this seasonal calendar still operates as a reference guide for gourmands to seek out the best times for seasonal delicacies and for health experts to plan nutritious diets.

In a single year, the system features 24 "solar terms," each lasting one day and occurring every two weeks. Each has its own name and characteristics. The Global Times is presenting a weekly series examining which foods and delicacies are best enjoyed during these periods, as well as tips on preserving general health.

The summer solstice, or the solar term xiazhi in Chinese (which falls on June 21 this year), is the longest day of the year, and often heralds the beginning of very hot spells of weather.

According to Xiong Anling, a traditional Chinese medicine (TCM) doctor who works at the Tong Han Chun Tang Pharmacy (20 Yuyuan Xin Road), it's common for people to feel sleepy and fatigued during the summer due to a lack of potassium in the body caused by sweating and irregular rest periods. 

"So the priority to maintain good health in summer is to stick to a regular work and rest routine, and try not to do any overtime at work," suggested the 72-year-old. He added that six to seven hours of sleep per night is a necessity and that, if possible, it's a good idea to have a half-hour nap in the afternoon.

Herbal care

Incense bags containing medicinal Chinese herbs, such as artemisia leaves, ageratum and cinnamon, can help to expel "coldness" from the body, and also strengthen the spleen and stomach; they can also stimulate the appetite. The incense bags can be hung up in a room as a decoration, or carried around with you. These incense bags can be found in any TCM pharmacy, and come in different shapes and sizes. And if you fancy a different combination of herbs, you can buy your own ingredients and container and create a custom-made incense bag. 

For people who don't like the strong smell of TCM herbs, aromatic flowers such as jasmine, rose and lavender are also an ideal choice. Pillows filled with dried petals have long been reputed as a way of soothing the nerves and helping to avoid insomnia during summer. To make your own aromatic pillow is simple: first, air-dry the petals in a cool, dark place; second, pound the dry petals into fine powder; and third, fill the pillow case with the powder.

Correct nourishment

According to TCM, a healthy diet after summer solstice should obey the rule of yang yang, which means to establish the yang function of the body.

"The emphasis of yang yang is to nourish the heart, so milk, yoghurt, egg, and bean products are essentials during this time," said Xiong.

But he warned that oily meat is not a good option in summer because people's digestive systems are relatively weaker during hot weather, and too much meat can increase the load on your system.

Bitter foods are strongly recommended for a summer diet, such as balsam pear, celery and towel gourd. These foods are excellent at expelling moisture from the body, alleviating fatigue, and soothing the nerves. As the old Chinese saying goes xin jing zi ran liang, which means you can keep cool despite the heat so long as you compose your mind and stay calm.

Xiong told the Global Times that people with weak constitutions, however, should not eat too many bitter dishes, because they are cold and purgative in nature, and can lead to diarrhea.

Don't sweat it

Dong bing xia zhi is an important idea in TCM, meaning that chronic diseases that are normally aggravated in winter, can be successfully treated during the summer. Common ailments that belong to this category include arthritis, asthma, and certain skin diseases.

Acupuncture, moxibustion, massage and applying herbal pastes to acupuncture points, are the main methods used in dong bing xia zhi, with the herbal pastes reputed to be particularly effective. The best time to apply this herbal paste is from the summer solstice onwards, and patients should avoid cooling drafts from fans and air-conditioners during periods of treatment.

"Proper exercise in the morning and evening are also encouraged during summer - but be careful to avoid sweating too much," suggested Xiong. "When you sweat, try to wipe it with a dry towel or a hot towel, as cold towels can block pores in the skin, trapping the coldness inside."