With temperatures expected to reach 30C (86F) over the weekend, there has been a heat-health alert issued for parts of England.
In London, the Midlands, eastern, and southern England, the alert is in effect from Friday morning until Monday morning.
People are urged to check on their vulnerable friends and relatives.
Sun protection factor (SPF), the large number on the front of your sunscreen bottle, is a term that most people are familiar with. The level of protection increases as the number rises.
It may be equally important to comprehend that many brands also display a five-star rating.
Your sunscreen's SPF value indicates how much UVB protection it offers. The star system provides you with information on how much UVB radiation is absorbed compared to how much UVA radiation is absorbed by the sunscreen.
Different wavelengths of solar radiation that enter the earth's atmosphere are referred to as ultraviolet A and B.
In addition to skin cancer, particularly squamous cell carcinoma (the second most common type), UVA is linked to skin aging, pigmentation, and skin cancer. Even through glass, it can affect human skin.
Sunburn is caused by UVB, which is also linked to certain types of skin cancer, including malignant melanoma and basal cell carcinoma (the most prevalent type).
It is advised to cover up and seek shade when the sun is at its hottest for maximum protection because sunscreen doesn't prevent all kinds of skin damage.
The . Number SPF. refers to how much UVB it allows in, not how much it blocks, when it appears on a sunscreen bottle.
Seven percent of the sun's rays, or one-fifth of them, can reach your skin when wearing sunscreen with an SPF of 15.
In comparison, SPF 30 blocks about 97 percent of UVB rays. Therefore, it blocks about 93 percent of UVB rays.
Accordingly, SPF 15 would theoretically provide you with 15 times the protection, or two and a half hours before you would burn, if you could only stay in the sun for 10 minutes without protection.
The . quantity of stars. refers to the ratio of UVB absorption to UVA absorption as a percentage. One to five stars are awarded, with five stars being the most efficient.
Because the UVA to UVB protection ratio is the same in low SPF sunscreens as in high SPF products, they may have high star ratings.
The best sunscreens have a high SPF and a high star rating.
These levels of defense presuppose that the sunscreen was applied in the best circumstances.
The truth is that most people don't apply sunscreen evenly, and it can rub off when you sweat or are in the water. According to experts, the majority of people only use half the recommended amount. .
No matter the SPF, sunscreen should be reapplied at least every two hours, according to the British Association of Dermatologists, who state that SPF 30 sunscreen is a "satisfactory form of sun protection in addition to protective shade and clothing.".
According to EU recommendations, sunscreen should only be marketed as offering "50+" SPF protection rather than using the ratings of 80 or 100 that are available in some countries.
SPF 50 offers about 98 percent additional protection, whereas SPF 100 would offer less than 100 percent, according to the company, which believes that this information may be misleading.
There is no product that can completely block the sun's rays.
There are many "extended wear" sunscreen products available that promote themselves as being used "once a day.". If properly applied, many claim to provide protection for up to eight hours. .
The risk that you may have missed a spot or that it will rub or wash off in that time, however, is too great, according to some dermatologists, so these products should still be applied at least every two hours, like any other sunscreen.
The failure of these products to live up to their claims was criticized in a Which? report from 2016. The average level of protection provided was discovered to have dropped by 74% after six to eight hours.
Check out more of Reality Check.
Send us your inquiries.
Observe us on Twitter.
