LONGECITY

Title.

That depends on your goals.  If it's a UVA lamp, the "burnless" variety, then the answer is zero, if you don't want to age your skin.  If it's a UVB lamp, it won't age your skin quite as much, but it will still age it.  It can also lead to various skin cancers.  The most important thing is to avoid any burning or peeling.   If you tan at low intensity for short times, it will take longer to get a tan but you might keep it longer.   The various parameters will change depending on your skin type and the strength of the lamps.  As you build up melanin in your skin, you will need longer exposures for the same effect.  I recommend covering your face and hands when tanning, since they get the most lifetime photodamage.

That depends on your goals.  If it's a UVA lamp, the "burnless" variety, then the answer is zero, if you don't want to age your skin.  If it's a UVB lamp, it won't age your skin quite as much, but it will still age it.  It can also lead to various skin cancers.  The most important thing is to avoid any burning or peeling.   If you tan at low intensity for short times, it will take longer to get a tan but you might keep it longer.   The various parameters will change depending on your skin type and the strength of the lamps.  As you build up melanin in your skin, you will need longer exposures for the same effect.  I recommend covering your face and hands when tanning, since they get the most lifetime photodamage.

Isn't it the case that all lamps contain UVA radiation and they only vary by the percentage of UVB radiation?

All tanning salons will have UVA (unless there is some filter on the lights which blocks it--which is extremely doubtful). They're therefore deadly--even compared to moderate sun baking (which, with sun screen use, isn't absolutely terrible).

Are you in a cold land locked country? Can you go to the beach?

If not, consider a DHA tan. You'll likely be able to find it in your country under some name. It's quite natural looking and the mechanism replicates a natural sun-tan quite well.

All tanning salons will have UVA (unless there is some filter on the lights which blocks it--which is extremely doubtful). They're therefore deadly--even compared to moderate sun baking (which, with sun screen use, isn't absolutely terrible).

 

Are you in a cold land locked country? Can you go to the beach?

 

If not, consider a DHA tan. You'll likely be able to find it in your country under some name. It's quite natural looking and the mechanism replicates a natural sun-tan quite well.

Yeah but I'm looking for healthy benefits of the sun. I don't care about the tan.

 

Yeah but I'm looking for healthy benefits of the sun. I don't care about the tan.

Why don't you sunbathe a bit then? For maximum UVB you should do that around local noon when Sun is high in the sky. 

 

All tanning salons will have UVA (unless there is some filter on the lights which blocks it--which is extremely doubtful). They're therefore deadly--even compared to moderate sun baking (which, with sun screen use, isn't absolutely terrible).

 

Are you in a cold land locked country? Can you go to the beach?

 

If not, consider a DHA tan. You'll likely be able to find it in your country under some name. It's quite natural looking and the mechanism replicates a natural sun-tan quite well.

Yeah but I'm looking for healthy benefits of the sun. I don't care about the tan.

 

Ah, then the answer is simpler. What healthy benefits? We should quantify them because there's a lot of pseudoscience around the sun. 

Vitamin-D? Get levels checked and supplement if necessary (see long thread in nutrition on supplemental vs sun vit-d).

Endorphins? Eh. Exercise.

Release of dopamine in the eye to prevent myopia? Eh. Bright light.

Even if you lived in a cave (which had bright lighting) none of these reasons would be good enough to risk cancer and get premature aging from a tanning bed vs just walking around in the sun (with sunscreen) or going to the beach (with sunscreen again).