Avoiding Sunburn

Knowing your Skin Type is imperative to avoiding overexposure to the Sun — most especially so when practicing sport, which normally keeps you out for longer periods of time in mixed environments. It is also very important to know the UV Index (UVI) for where you will be that day, and how it will be enhanced by the terrain or environment in which you will be practicing your sport.

The equations in the table below can be used to calculate how long you can stay in the Sun without sunscreen before you start to burn (i.e. before Minimal Erythemal Dose, or MED, occurs).

SKIN TYPE: 1
Maximum time in the Sun = 67 min / UVI

SKIN TYPE: 2
Maximum time in the Sun = 100 min / UVI

SKIN TYPE: 3
Maximum time in the Sun = 200 min / UVI

SKIN TYPE: 4
Maximum time in the Sun = 300 min / UVI

SKIN TYPE: 5
Maximum time in the Sun = 400 min / UVI

SKIN TYPE: 6
Maximum time in the Sun = 500 min / UVI

UV Exposure

 

Many factors affect the UV intensity, which subsequently alters the UV Index. This then affects the amount of time that you can spend in the Sun before starting to burn. The following information corresponds to the Environmental UV Reflection diagram (left), and demonstrates how your environment or terrain affects the level of UV radiation that you are exposed to:

85% increase from snow reflection

100% increase at 3000m altitude

25% increase from white-water reflection

 80% of UV rays pass through cloud

20% from sand and grass reflection  – and 40% when wet

15% reflection from concrete buildings

50% can be reflected into shaded areas

50% UVB and 80% UVA passes through the upper 50cm of water

50% increase from water reflection

—  THE SUN  |  EXPOSURE  |  SPF  |  UV INDEX  |  SOLAR RAYS  —

 

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