The comprehensive physiological changes caused by cave environments in the human body are manifested in the following four aspects:
1. Disruption of Biological Rhythms—The absence of seasonal or time-based changes in caves disrupts the “biological clock” and extends its cycle.
2. Climate Chaos—The lack of temperature and humidity variation in caves may lead to a disoriented state after prolonged stays.
3. Sensory Chaos—Extended exposure to quiet, dark environments without familiar visual or auditory stimuli can result in
impaired function, leading to central nervous tension and even hallucinations.
4. Effects of Cold—Cold can trigger protective mechanisms in the human body for dealing with stress and extreme stress, resulting in slow and rapid stress responses.
Human ancestors had long periods of living experience, so humans should have a special connection with caves. The continuous discovery of cultural relics in caves demonstrates the long and close relationship between humans and caves.
The discovery of Peking Man in Zhoukoudian, Beijing, the hanging coffins in the cliff caves of the Three Gorges on the Yangtze River, the cave paintings found across Europe, various cultural artifacts discovered in caves worldwide, and the widespread nitrate pits in caves all reflect humanity's historical use of caves. Nitrate pits are a unique phenomenon in Chinese caves, demonstrating how ancient people extracted nitrates from nitrous soil, reflecting their ingenuity and also the backwardness of industry at the time.
In addition to the accumulation of cultural relics, caves also contain large amounts of ancient biological remains, providing us with abundant and detailed historical data.
Protection of Caves
This is an important issue. Currently, neither the national nor local governments have specific laws or regulations to protect caves, and conservation efforts are only carried out at the civilian level. Therefore, as cave explorers or enthusiasts, everyone should actively, consciously, and voluntarily promote and implement protection awareness. In caves, apart from trash and photos, nothing else should be taken. No vegetation should be damaged, no cave animals hunted, and no cave water polluted. In group settings, single-file movement is recommended. Abroad, even excretion is managed using special containers that are taken out upon departure.
Cave development should follow the principles of scientific planning and scientific development. Practice has shown that hasty development without comprehensive surveys, mapping, and planning—and lacking protective measures—can lead to serious consequences for the resource. For developers, cave resources will also not have long-term commercial viability.
Every cave resource is our treasure. In addition to enjoying them, we must ensure that future generations can see them too. I hope everyone who reads this article can truly take action to care for and protect caves.
How to Ensure Safety in Caves
When entering a cave, the first priority is to ensure sufficient lighting. Using reliable lamps and bringing ample batteries is a good practice. If staying for a long time, it is essential to prepare at least two backup lamps. Wearing a helmet ensures safe movement inside the cave (except for those who have trained—or naturally possess—an iron head).
When entering unfamiliar caves, there should be at least two people. If lost, avoid wandering around, stay calm, and waiting in place for rescue is the best approach.
Cave temperatures are relatively low, so it’s important to keep warm when resting. A sleeping pad with a fill of 400 grams or more is ideal. It’s also advisable to bring a fleece layer.
Water in caves must be boiled before drinking. If the water source isn’t very clean, it’s best to filter it several times before boiling. When water conditions are unknown and no protective gear is available, avoid wading through water. Take waterproofing measures (mainly for batteries and electrical equipment).
While moving in a cave, avoid running or jumping. When no equipment is needed for ascending or descending slopes, try to use both hands and feet.
In unfamiliar passages, let the more experienced team member go first. Mark the route as per regulations along the way.
Each person should carry their own batteries, food, and other personal items.
Safety is the basic principle of any activity. Having a safety mindset not only protects oneself but is also a responsible attitude toward the team. Such individuals are always welcome.
Professional cave explorers should have professional skills, reliable equipment, and good teamwork spirit.
World and Domestic Cave Data
Longest Cave System in the World: Mammoth Cave in the USA, stretching 556,849 meters
Deepest Cave in the World: Krubera Cave in Georgia, with a depth of 1,710 meters
Longest Cave System in China: Shuanghe Cave in Guizhou, measuring 100,044 meters, currently ranked 16th in the world
Deepest Cave in China: Qikeng Cave in Wulong, Chongqing, with a depth of 920 meters
China's largest cave chamber: Guizhou Gebi River Miao Hall, 116,000 square meters
Human response to changes in oxygen and CO₂ levels
Effects of oxygen
20.9% – favorable for breathing, normal flame combustion
19% – no discomfort felt yet, flame combustion reduced by 1/3
17% – increased heart rate and difficulty breathing during strenuous work, no effect at rest, flame extinguished
15% – oxygen deficiency in the body, rapid breathing and pulse, impaired judgment, muscle function disruption
12% – noticeable oxygen deficiency
Effects of carbon dioxide
1% – increase in breathing rate and depth
3% – faster breathing and pulse, flickering flames
4% – headache, dizziness, tinnitus
6% – severe breathing difficulty, poor acetylene lamp combustion
7–10% – unconsciousness within minutes, death, acetylene lamp extinguished