Over time, the cell, like a small house, accumulates “garbage” — damaged proteins, worn-out parts, or invading microbes. Autophagy works like a cleaning service: it finds this garbage, packs it into special “bags,” processes it, and returns useful components to circulation. This process maintains cell health, protects against disease, and supplies the body with energy during exercise and fasting.
In the study, 10 healthy men (average age 23) were immersed in water at 14°C for an hour every day for a week. The researchers monitored proteins in the blood to assess the impact of the cold on key cellular responses: autophagy, inflammation, and heat shock.
When cells are suddenly cooled, the structure of proteins is disrupted — they begin to fold and stick together incorrectly. In response, the body launches a protective mechanism. Special heat shock proteins (HSPs) help restore the correct shape of damaged proteins, prevent their accumulation, and direct irreversibly damaged molecules for disposal, including through the process of autophagy.
Initially, the participants showed autophagy dysfunction, which manifested itself in the accumulation of the p62 protein. It acts as a “marker” — it binds to damaged cellular components and prepares them for utilization through autophagy, and is then “thrown out” along with them. If p62 accumulates, it means that the process is disrupted. In parallel, the level of caspase-3, responsible for apoptosis — self-destruction of cells, increased. These data demonstrate a key mechanism of the cellular response to stress: when autophagy (p62) is ineffective, the program of controlled cell death (caspase-3) is activated.
By the fourth day of the experiment, the p62 protein level had decreased (although it remained above baseline), while the caspase-3 content remained high. Apparently, autophagy could not cope with the stress of the cold. However, by the seventh day, the situation changed: autophagy-related activity began to prevail over cell death signals. The cells began to tolerate the cold better.
Exposure to cold may help prevent disease and even slow aging at the cellular level, scientists say. But more research is needed.