The idea of humans surviving being frozen solid in ice has long captivated imagination, appearing often in popular culture. While dramatic tales suggest remarkable resilience, the scientific answer to whether a human can genuinely survive freezing is complex.
What Happens When the Body Freezes
When human tissues truly freeze, water within and around cells turns into ice crystals. This process is damaging because water expands as it freezes, rupturing cell membranes and other cellular components. Ice crystals create mechanical stress, distorting cellular structures and leading to destruction upon thawing.
Beyond physical damage, freezing causes osmotic stress as water is drawn out of cells, leading to cellular dehydration. Upon rewarming, rapid water influx can cause cells to swell and burst. This widespread cellular damage extends to vital organs, disrupting their function. Blood vessels are also susceptible to damage, impairing the delivery of oxygen and nutrients.
The Difference Between Freezing and Severe Hypothermia
It is important to distinguish between being truly frozen and experiencing severe hypothermia, a significant drop in core body temperature below 35°C (95°F). Unlike frostbite, severe hypothermia does not involve ice crystal formation within the body’s cells. Instead, the body’s internal temperature decreases, dramatically slowing normal physiological functions.
This metabolic slowdown reduces the demand for oxygen and energy in tissues. This protective effect can preserve organs, especially the brain, by mitigating damage from oxygen deprivation. Therefore, instances of survival attributed to “freezing” are almost always cases of profound hypothermia, where the body’s systems are severely depressed but not irreversibly destroyed by ice crystal formation.
Real-World Instances of Survival
Cases of individuals surviving extreme cold exposure are almost exclusively instances of profound hypothermia, where medical intervention played a crucial role. A notable example is Anna Bågenholm, a Swedish radiologist who in 1999 was trapped under ice for 80 minutes. Her body temperature dropped to 13.7°C (56.7°F), and her heart stopped for several hours, yet she survived.
Such survival is possible because extreme cold significantly slows the body’s metabolic processes, including oxygen consumption. This protects the brain and other organs from damage during reduced blood flow. Intensive medical interventions are critical for resuscitation, often including cardiopulmonary resuscitation (CPR) and active internal rewarming techniques like cardiopulmonary bypass or warmed intravenous fluids. While remarkable, these events remain rare and depend heavily on rapid rescue and specialized medical care.
Animals That Survive Freezing
In contrast to humans, some animals possess biological adaptations that allow them to genuinely survive being frozen solid. The wood frog is a prime example. These amphibians can endure up to two-thirds of their body water turning to ice, with their heart and breathing stopping entirely.
Their survival is attributed to natural cryoprotectants, such as glucose and glycerol. These compounds act like antifreeze, preventing damaging ice crystals from forming inside cells and stabilizing cellular structures. Instead, ice formation is largely restricted to spaces outside the cells, minimizing cellular rupture. Humans lack these specialized physiological mechanisms, making true freezing a lethal event for our species.