If cold water immersion is, anecdotally, deemed beneficial, then can cold air therapy have the same or better effects on the human. Now by the same or better I mean performance improvements and/or health improvements. Lets first look at the facts.
Cold water immersion at 12C or 53.6F is very cold at least for normal swimmers, for example in ITU triathlons water temp below 14C or 57.2F means the swim portion is wetsuit mandatory due to risk of hyperthermia, even though immersion times are from 8-60 mins. In cold air of similar temperatures no such rule exists and riding a bike for 30 mins to 5 hours following a swim is not uncommon and in much lower temperatures, so cold air immersion is likely to last for much longer than cold water immersion.
When we look at cold immersion in water or air, we need to consider the reason or purpose of the immersion, whether for therapeutic reasons or force of circumstance such as in races or training and understand the effects on the human of such immersion. But setting aside races, training and other possible circumstances we can focus on purely therapeutic modalities to determine if there are benefits for cold immersion and the big question is can cold air immersion deliver any therapeutic benefits?
Cold air immersion can easily be achieved in colder or temperate climates where natural conditions often offer air temperature of 5 Celsius and below so that cold air immersion can be managed for any desired length of time. But in tropical or similar climates cold air immersion may not be practical except through a purpose built climatic simulation chamber.
Question is, are there benefits from simple whole body skin exposure to cold temperatures? The variables would be air temperature, airflow, exposure time. Other variables could include altitude and acclimation but these are not considered here. See ref A.
It seems from the research that cold water immersion beneficial effects come about for several reasons, enhance calorie usage due to shivering, hormonal changes with an increase in adrenalin and other hormones that could help with depression and also the anti-inflammatory effects of cold temperatures just as ice does. Now these benefits have been studied and many people are convinced of their efficacy, but there are clear variables such as temperature and time of immersion and with this comes risks especially for the unwary. Hypothermia and cold damage to cells and skin are exacerbated with total immersion in cold water and clearly this can be dangerous, after all we know the Titanic story too well.
The risks associated with cold air immersion are much less than cold open water swimming or plunging, a short walk in 5 degree air could have the same benefits, certainly shivering occurs, mitochondrial increase in energy must also occur as it does in water and the effects on brown fat are probably the same. But the risks are much lower in air and could be even more beneficial for people looking for health benefits.
References :
A. Cold air immersion https://www.nature.com/articles/ejcn2016223
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