Therapeutic hypothermia certainly is an extremely useful short-term treatment for hypoxic and ischaemic injury to tissues (caused by loss of blood flow and/or oxygen) and is part of the protocol for treating people in intensive care who have had out of hospital cardiac or respiratory arrest as well as being used during heart surgery in cardiopulmonary bypass. In addition there is currently research into treating people who have just had heart attacks and strokes, both conditions where there is acute loss of blood flow due to a clot.
However, there is little evidence as regards use of chronic (long term) hypothermia to prevent aging. While severe hypothermia does suppress cellular respiration and slow down metabolism and bodily function, it also often causes other abnormalities such as:
- Disturbances in cardiac conduction that can lead to cardiac arrest
- Markedly reduced blood flow to skin and limbs which can lead to tissue death in fingers, toes, etc.
- Clotting dysfunction (haemorrhage if there is any injury)
- Pulmonary oedema - fluid in the lungs causing inability to oxygenate and/or ventilate the blood
- Increase in infections
There is, however, quite a lot more evidence in regards to slowing down cell ageing from oxidative stress using diet energy restriction and this has been replicated in rodents.
In other words, there really isn't any good evidence at this stage in regards to long term hypothermia, but currently, given the high risks of cardiac dysfunction and death, without invasive monitoring and intervention (such as in an ICU) it is not feasible.