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Could humidity hold the key to looking younger?
It is well known that temperature and ultraviolet radiation can impact on the skin. However, a recent study published online in the Journal of the European Academy of Dermatology and Venereology* reviewed the evidence around another changeable climatic factor – humidity – on both healthy and diseased skin.
The research found that even a drop in humidity of just 30 per cent can lead to the formation of fine wrinkles in as little as 30 minutes. Furthermore, low humidity can cause decreased skin elasticity, increased skin roughness and may worsen some skin disorders.
Relative humidity (RH), rather than absolute humidity, is the most common way of measuring the moisture content of the air. It is the amount of water vapour (moisture) in the air compared to the maximum amount that the air could hold at a given temperature, and is expressed as a percentage. A good range for relative humidity within the home is between 30 per cent and 60 per cent.
The review, funded by the Skin Health Alliance, looked at laboratory based studies as well as studies of people in the general population.
One study exploring the effect of low humidity on healthy human skin on the forearm and the cheek, before and after three or six-hour exposure to conditions of low humidity, measured the water content of the skin and the skin’s texture. The results demonstrated a significant decrease in the water content of the skin of the arm and cheek after three and six hours. The skin also showed increased roughness.
Even a 30 per cent difference in relative humidity can affect skin properties within just 30 minutes, according to another study, which measured elasticity and fine wrinkles on the eyelids of 20 volunteers, first after 30 minutes in a high-humidity room (70% RH) and again after 30 minutes in a low humidity room (40% RH). The authors found decreases in moisture levels and elasticity, and significant increases in fine wrinkles, after acclimatisation to low humidity compared with a high humidity environment. Exposure to low humidity significantly increased the area ratio of fine wrinkles with uneven skin textures.
In a study into the effects of water nanodroplets (mist) on skin hydration, 12 healthy volunteers with normal skin spent the first 60 minutes in an air conditioned test area without mist, maintained at 24°C and 35 per cent relative humidity. At this point, there were no significant differences in skin hydration levels between the mist group and the control group.
The participants were then either maintained in the same conditions as the test area (control group), or else in the same conditions as the test area with the addition of mist, for an additional 120 minutes. Skin elasticity was significantly increased in the group with mist compared with the control group at the forehead and cheek. This implies that the mist caused hydration of the skin and produced a subsequent softening effect.
Studies also suggest that low indoor humidity may increase the risk of childhood eczema, and worsen irritant eczema.
James Stalley of the Skin Health Alliance who funded the research, said: “We often talk about the impact of UV on skin aging, but now evidence is emerging that humidity may also play a major part. Reviews like this are important because they collate and scrutinize the many studies on one topic, allowing for the results to be cross referenced and parallels to be drawn. This study brings together a range of data on humidity, to allow us to see where the most interesting areas for future therapies will lie, be they in the medical or cosmetic sectors.”
For further information about this research review please contact the Skin Health Alliance. Tel +44 (0)20 7391 6070; Email firstname.lastname@example.org .
*J Eur Acad Dermatol Venereol. 2016 Jun 15. doi: 10.1111/jdv.13707.
Ambient humidity and the skin: the impact of air humidity in healthy and diseased states.
Goad N, Gawkrodger DJ.