The Science Behind Hot And Cold Therapy
Skincare treatments are ever-evolving, and cold and hot therapy are the new in-things
The beauty industry has proven itself to be innovative. There is no shortage of unusual face treatments; think bird poop facials, vampire facelifts, snake and bee venom skincare, vagina steaming, and Korean face slapping, just to name just a few.
This can also be seen in the use of high-low temperatures for aesthetic and wellness purposes, from sweat-inducing hot yoga and infrared saunas to the chilling processes of cryotherapy and fat-freezing. And since most of us don’t have the luxury of our own steam bath or cryo chamber at home, beauty brands have responded with both warming and cooling skincare products and DIY gadgets.
But beyond enjoying the immediate comfort these products deliver, how do we know if we should be turning up the heat or chilling out in our skincare routines?
According to Dr Kok Wai Leong, dermatologist at DS Skin & Wellness Clinic, heat therapy may be useful for wound healing as it boosts blood flow to the skin, bringing more oxygen and nutrients for skin repair.
“Heat also alleviates swelling in skin inflammation or infections. And there has been research to show that skin permeability increases with heating of the skin. Theoretically, this will increase the absorption of treatment products that are applied.”
However, the circulation-boosting benefits of mild heat are likely limited. “Just like applying a hot towel on your face on the airplane or when you are in a hot sauna, you feel refreshed because of the increased blood flow to the skin and the opening of your pores, but such effects are short-lived,” he explains.
Although there is no ideal temperature range at which skin-warming products are the most effective or comfortable – it varies between individuals – what’s worth bearing in mind is that the application of heat should always be gradual and controlled.
“Unregulated use of heat-generating devices on your skin may lead to heat build-up, which causes
skin irritation and inflammation instead of repair,” says Dr Kok. “In a real world setting, it is difficult to ensure that skin temperature remains constant. Over-heating or prolonged heating can occur, causing skin damage. And even with short-lived but rapid heating, thermal-related heat effects like burns and blisters may develop,” he cautions.
Dr Low Chai Ling, founder of SW1 Clinic, also cautions that heat therapy is contentious at best, with its
effectiveness dependent on the heat source, how long the skin is exposed and at what temperatures.
“Recent evidence indicates that infrared and heat may induce premature skin ageing, just like UV radiation. Not only do they degrade collagen and decrease collagen production, heat energy can also result in the development of solar elastosis,” she says. Solar elastosis is a disorder caused by sun damage, in which skin loses its elasticity and appears yellowed and thick.
“Cooling products like sheet masks and massagers do temporarily relieve skin inflammation and itching. They also help to address dark circles and eye fatigue, which can be partially caused by vasodilation or enlargement of blood vessels in the skin around eyes,” he says.
However, Dr Low warns that there are potential downsides to cold therapy too. She says: “In the short term, cold therapy may make skin look a little brighter and reduce redness due to the superficial vasoconstriction effect, but extreme cold can lead to rashes, frostbite and other issues.”
Dr Kok adds: “There have been reports about the anti-inflammatory benefits and vasoconstricting action of cold therapy, but the effects are transient. While they may be useful in the short term for inflamed or sensitive skin, they should not be used as the main treatment.”
In addition, cooling products may contain alcohol or menthol. The latter delivers a cooling sensation without an actual fall in skin temperature.
“These products may lead to evaporative water loss. They should be used together with a moisturising agent to prevent dryness or irritation,” he explains.
Text: Ho Guo Xiong/HerWorld