What happens in the body when diving, how deep can a person dive, what should we pay attention to in order to safely explore the depths of the sea and what is decompression all about?
Freediving: Into the depths without equipment
Diving without equipment, also known as apnea diving or freediving, is a fascinating and ancient practice in which humans explore the underwater world without any technical aids. The origins of freediving lie many thousands of years in the past, when it was used primarily to collect food, but also resources such as pearls and sponges, from the depths of the sea.
Unlike scuba diving, the freediver relies solely on his or her own physical abilities and breath control. This form of diving requires a high level of physical fitness, mental strength and good technique to safely explore the depths of the sea.
How does freediving work?
Anyone who wants to learn freediving usually starts with special breathing exercises. The focus is mainly on lengthening the exhalation. This means that you train to hold your breath for longer and longer. The technique can theoretically be learned privately, but it is recommended to learn freediving in a club to cover all safety aspects. Here, interested parties can learn how to improve their physical and mental fitness and receive tips on breathing techniques. There are also pressure equalization exercises and nutritional tips.
Since diving into depth changes the processes in the body (more on this later in the article), there is a high health risk involved in freediving – which makes it all the more important to seek professional advice from experts.
World records and personal limits
The current world records in freediving are impressive. The use of weights or fins has a significant impact on the duration of the dives and the depths that can be reached. Accordingly, there are different disciplines depending on which aids are used. For example, the Austrian Herbert Nitsch holds the record for so-called no-limits diving (the aim is to get as deep as possible) for men with a depth of 214 meters. The current women’s record is 101 meters – held by the Italian Alessia Zecchini. Such depths require intensive preparation and years of training. For most freedivers, the personal limit lies much further below the water surface. A depth of 30 to 40 meters is already a remarkable achievement.
Risks and safety precautions
Freediving involves considerable risks, particularly due to lack of oxygen and pressure injuries, which can lead to unconsciousness and subsequent drowning and to injuries to the eardrum or lungs. Safety precautions such as diving in a buddy system – always in pairs – regular training in rescue techniques and precise knowledge of one’s own physical limits are essential to avoid accidents. Inadequate preparation and overestimation of one’s own abilities, but also unforeseen events such as strong currents, can lead to serious accidents. Time and again, people die when trying to go beyond their own limits – for example, the Russian Natalia Molchanowa, one of the most famous freedivers in the world, who did not return to the water surface after one of her dives in 2015. Her body was never found.
Scuba diving: exploring the depths with equipment
Anyone who wants to go underwater for longer dives independent of freediving can learn the basics at a diving school. This also includes knowing the right equipment, which can vary depending on the type of dive. Diving mask, snorkel and diving fins are part of the basic equipment. In addition, a diving suit, a buoyancy compensator (it helps regulate buoyancy thanks to the air supply), a regulator and a diving tank are required. A dive computer, depth and pressure gauge as well as a weight system and a signal buoy are also important. Other equipment such as an underwater lamp, a dive knife and an underwater compass may be required depending on conditions and preferences.
Basics of scuba diving
This form of diving uses technical aids such as regulators and oxygen bottles that allow you to breathe at depth, so you can stay underwater longer and deeper. Scuba diving requires a diving license, which means thorough training and specialist knowledge of the equipment and correct behavior underwater.
How deep can you dive with equipment?
The maximum safe diving depth with standard diving equipment (see above) is about 40 meters . However, anyone who is just starting out diving and is getting their Open Water Diver license should not go deeper than 18 meters at first. Technical diving with special gas mixtures and equipment enables depths of up to 100 meters and more. The current answer to the question “How deep can a person dive?” is: The deepest depth ever reached in technical diving is 332.35 meters – reached by the Egyptian Ahmed Gabr in the Red Sea in 2022.
Modern equipment and technical possibilities
Modern diving equipment and technological advances have significantly expanded the possibilities of deep-sea diving. Rebreather systems, which recycle the exhaled gas, enable longer dives. In addition, special dive computers allow precise monitoring of the diving depth and time as well as the ascent speed and ensure that there are no problems caused by gas build-up in the body. Read the next paragraph to find out why this can be problematic.
Psychological and physical aspects of deep diving
The role of nitrogen in diving
When diving, nitrogen from the breathing gas in the diving tank reaches the brain via the lungs and blood. While the water pressure increases with increasing depth, it decreases again when surfacing. In the process, nitrogen – due to the falling ambient pressure – enters the blood again. If this process happens too quickly, the nitrogen cannot be returned to the blood quickly enough and nitrogen bubbles form, which can cause the cardiovascular system to collapse.
At a depth of 20 to 30 meters, divers can also fall into a state of intoxication. This so-called deep-sea intoxication can be caused by the effect of nitrogen on the brain and nervous system and can manifest itself in feelings of happiness, but also confusion and unconsciousness. This makes it all the more important to never dive alone, as those affected are often no longer able to properly assess the situation.
Training and preparation
Intensive training and careful preparation are crucial to mastering the physical and mental challenges of deep diving. This includes breathing exercises, physical fitness and learning relaxation techniques.
Resilience of the human body
The physical limits of the human body determine how deep people can dive. The oxygen level in the blood, the stress of water pressure and the ability to withstand cold limit the maximum depth that can be reached (about 40 meters with standard equipment).
Decompression sickness: What to look out for?
Decompression sickness, also known as diver’s sickness, occurs when a diver surfaces too quickly and the drop in pressure causes gases dissolved in the tissues and blood, mainly nitrogen, to form bubbles. This can lead to serious health problems because they block the blood vessels and lead to so-called gas embolisms. Symptoms of decompression sickness can include pain in the joints, dizziness, nausea and, in extreme cases, paralysis or unconsciousness – in these cases, a doctor should definitely be consulted.
In order to be able to surface safely without decompression stops, a depth of up to 18 meters should not be exceeded. If you go deeper, you have to stay at certain depths for some time during the ascent. The staggering and duration of the stops vary from dive to dive and depend on the depth, the dive time and the breathing gases used.
These stops are especially important to break down the nitrogen that accumulates in the tissues during diving, so that no bubbles form in the blood. Since the nitrogen content in the body is also increased after diving, divers should not board an airplane for at least 24 hours after the last dive, as the internal pressure in an airplane is so reduced that the formation of gas bubbles could lead to decompression sickness, even after a certain time delay.
Pressure equalization
Most people feel pressure on their ears from a depth of just a few meters – this is caused by the water pressure, which increases with depth and creates an imbalance between the external water pressure and the internal air pressure in the middle ear. This is why it is essential when diving to learn how to equalize the pressure . While some people find it very easy to equalize the pressure by swallowing or “holding their nose and blowing with their mouth closed”, others need a bit of practice. The pressure on the body increases by one bar for every ten meters – which is why the pressure should be equalized every ten meters. If the pressure equalization does not work, this can result in what is known as barotrauma; tissue damage. When diving, the middle ear is usually affected; typical health consequences are pain and hearing loss.
Why don’t whales get decompression sickness?
Whales and all other marine mammals can dive to extreme depths without being exposed to the harmful effects of rapid pressure changes thanks to special physiological adaptations. During their deep dives (sperm whales can dive to depths of up to 3,000 meters), they lower their heart rate and reduce blood flow to non-vital organs, which means less nitrogen gets into the blood. Their lungs collapse in a controlled manner at depth, which prevents nitrogen from being absorbed into the bloodstream. They also have a special protein structure in their blood and tissue that allows them to efficiently store and process the dissolved nitrogen.
Diving: Between fascination and risk
As is often the case in life, diving is a balancing act: as much fun as exploring the underwater world can be, it also involves dangers that you should be aware of. But it is precisely this mixture of closeness to nature, beauty and risk that makes the sport so fascinating.
The beauty of the underwater world
Diving gives you an insight into a world far removed from our everyday reality, full of living creatures and unique landscapes. Coral reefs, underwater caves and diverse sea creatures offer unforgettable experiences and an insight into an ecosystem that remains hidden from many people. Underwater, the joy of discovery and adventure meet absolute peace, isolation and connection with nature. In addition, the different diving areas around the world offer an exciting variety of opportunities to discover new natural spectacles underwater.
Protecting and preserving the oceans
The beauty of the underwater world goes hand in hand with the responsibility to preserve it. Divers are often active conservationists who work to preserve marine ecosystems and biodiversity and to combat pollution and overfishing. Because when you get to know this unique world and the importance of its diversity, you become more aware of how worth protecting it is. If you want to get involved, you can find NGOs or volunteer groups in many places that you can join. In general, it is advisable to take certified, local diving instructors with you when diving on holiday. They not only know the best places, but also how to move around safely and carefully.
Dangers under water
Diving can be very demanding both physically and mentally. That’s why rules should be followed to ensure a safe dive. But beyond your own human abilities, the ocean is of course also an ecosystem that should not be explored without prior knowledge and a certain amount of respect. Knowledge of poisonous or dangerous sea creatures, currents and boat traffic is therefore the basis for a safe dive. That’s why it’s a good idea to join local groups and diving schools, especially when diving in unfamiliar areas.
Learn to dive safely
Anyone who wants to experience the fascination of the ocean should contact a certified diving school that offers special courses for beginners – both for diving with scuba diving and for free diving. Here, not only the basic theory and the most important diving signals for communication under water are learned. The dives are also accompanied step by step to ensure a safe start. Often, practice is carried out in pools or swimming pools before heading out into open waters, i.e. lakes or the sea. Anyone who would like to go diving but is unsure about their own physical fitness or has had problems in the past, for example with equalizing pressure, can undergo a diving fitness test beforehand . These are carried out by diving doctors. Here, the cardiovascular system, ears, lungs, but also mental state, communication skills and dealing with dangerous situations are examined.