Does Tanning Burn Calories or Make You Lose Weight?

By David Gray • Updated May 2026 • Medically reviewed May 2026
woman tanning

Tanning does technically burn calories — but not in any meaningful way. Your body burns roughly 50 to 100 calories per hour simply lying still, whether you’re on a sun lounger or a sofa. That’s about the same as napping.

What’s more interesting is what sunlight actually does to fat cells and your metabolism. There’s real science behind it, and it’s more nuanced than the usual “tanning burns fat” claims you’ll see circulating online. Some of those claims have a kernel of truth. Others don’t.

This article breaks down the science honestly — including how many calories tanning actually burns, what a 2018 University of Alberta study found about sunlight and fat cells, how UV exposure affects metabolism, and why tanning beds aren’t quite the same story as the sun.

Key Takeaways

  • Tanning burns roughly 50–100 calories per hour — far less than any form of active exercise.
  • Sunbathing in a warm environment actually reduces calorie burn compared to being in cooler conditions, because your body doesn’t need to generate its own heat.
  • A 2018 University of Alberta study found that blue light from the sun causes subcutaneous fat cells to shrink — but researchers caution this is not a weight-loss method.
  • Tanning beds do not emit significant blue light, so they likely don’t produce the same fat-cell effect as direct sunlight.
  • UV exposure (sun or tanning bed) may mildly boost thyroid activity and metabolism, but the effect is modest.
  • Sweating while tanning doesn’t mean you’re burning more calories — sweat is a cooling response, not a sign of energy expenditure.
  • Self-tanning products have zero metabolic effect — they don’t burn calories or fat in any way.
  • There are far safer and more effective ways to lose weight than UV exposure.

How Many Calories Does Tanning Actually Burn?

Your body burns calories constantly, even at rest. The minimum energy your body needs just to keep your organs functioning is called your basal metabolic rate (BMR). For most adults, this works out to somewhere between 1,400 and 2,000 calories per day — roughly 60 to 85 calories per hour.

When you’re sunbathing, you’re burning a small amount of calories simply by existing. Estimates typically put it at around 50 to 100 calories per hour, depending on your body size and metabolic rate. To put that in perspective, a brisk 30-minute walk burns around 150 calories. A light jog burns around 300. Tanning isn’t close to either.

There’s a counterintuitive twist here too. Your body burns more calories in cold environments because it has to generate heat internally to keep your core temperature stable. In the heat of the sun, that process is reversed — your body is being warmed from the outside, so it actually needs less energy for temperature regulation. That means lying in hot sun may burn slightly fewer calories than lying in a cool room.

So if you’re asking whether tanning burns calories — yes, technically. But it’s not doing anything your body wouldn’t be doing anyway.

Does Tanning Burn Fat?

This is where it gets genuinely interesting. A 2018 study published in Scientific Reports by researchers at the University of Alberta found that blue light wavelengths from the sun penetrate the skin and directly affect fat cells just beneath the surface.

When these blue light wavelengths reach subcutaneous fat cells (the fat stored just under the skin), the lipid droplets inside those cells shrink in size and are released from the cell. In simple terms, the cells end up holding less fat. [Shum et al., Scientific Reports, 2017]

The researchers believe this could partly explain why many people in northern climates tend to gain weight during the winter months, when sunlight is limited. As Peter Light, professor of pharmacology at the University of Alberta and senior author of the study, put it: “If you flip our findings around, the insufficient sunlight exposure we get eight months of the year living in a northern climate may be promoting fat storage.”

That’s a fascinating finding. But Professor Light is also careful to point out that this is an early observation, and that pursuing sun exposure as a weight-loss strategy is “not a safe or recommended way to lose weight.” The amount of blue light needed to produce these effects, and the depth to which it penetrates, are still being studied. It’s also worth noting that visceral fat — the deeper fat stored around your organs — sits too far below the surface for light to reach.

So does tanning burn belly fat? There may be some minor effect on subcutaneous fat near the surface, but it’s nowhere near significant enough to treat as a weight-loss tool, and it comes with real skin health risks.

Does Tanning Boost Your Metabolism?

UV light exposure — from the sun or a tanning bed — appears to have a mild stimulating effect on the thyroid gland. Since the thyroid controls your metabolic rate, this means UV exposure could, in theory, lead to a slightly higher rate of calorie burning at rest. [Moszczyński et al., Endokrynologia Polska, 1987]

This is likely one of the reasons many people feel more energised and alert after spending time in the sun. A small metabolic lift — combined with the mood-boosting effects of sunlight and vitamin D production — can leave you feeling noticeably better after a sunny afternoon.

That said, the metabolic boost from tanning is mild. It’s not going to transform your calorie burn in a meaningful way. If boosting your metabolism is genuinely your goal, regular exercise, building lean muscle mass, staying well hydrated, and getting enough sleep will all have a far greater effect.

You can learn more about how UV exposure relates to vitamin D in our guide to whether you can get vitamin D from a tanning bed.

Does Sweating While Tanning Mean You’re Burning Calories?

This is one of the most common misconceptions around tanning and calorie burn — and it’s worth clearing up properly.

Sweating is your body’s cooling mechanism. When your skin temperature rises, your body produces sweat to help regulate its temperature. During exercise, you sweat because your muscles are generating heat as a byproduct of burning energy. So in that context, sweat is associated with calorie burn — but only because of the exercise itself, not the sweating.

When you’re sunbathing, you sweat because the sun is heating your skin from the outside. Your body isn’t generating that heat through energy expenditure — it’s just responding to an external heat source. The sweat doesn’t indicate calorie burn in any meaningful sense.

The weight you might lose after a sweaty sunbathing session is almost entirely water weight, which is replenished the moment you drink something. It isn’t fat loss.

Do Tanning Beds Burn Calories or Fat?

The calorie burn from a tanning bed session is similar to sunbathing — negligible. Your body is warm and relaxed, and any calories burned are simply those your body burns at rest.

The bigger difference is on the fat-cell side. The University of Alberta study found that it’s specifically blue light — part of visible sunlight — that causes subcutaneous fat cells to shrink. Tanning beds primarily emit UVA and UVB radiation, not the blue light wavelengths responsible for this effect. So the fat-shrinking benefit observed with sunlight is unlikely to occur with tanning bed use.

Tanning beds do emit UV radiation, which may produce the same mild thyroid and metabolism stimulation as natural sun. But people typically spend much shorter sessions under a tanning bed than they would sunbathing, so even that modest effect is limited.

If you’re new to tanning beds, our tanning bed tips for beginners guide covers everything you need to know to get started safely. And if you’re curious about hybrid beds that combine UV tanning with red light therapy, we also have a full breakdown of what a hybrid tanning bed is and how it works.

What About Self-Tanning — Does It Burn Any Calories?

Self-tanning products work by reacting with the dead skin cells on the surface of your skin using an ingredient called DHA (dihydroxyacetone). This produces a tan-like colour without any UV exposure. It’s a purely cosmetic chemical reaction at the surface level — there’s no UV light, no heat, no metabolic effect of any kind.

So no, self-tanner doesn’t burn calories or affect fat in any way. What it does do is give you a natural-looking tan without any of the health risks that come with UV exposure. If looking tanned is the goal and weight loss isn’t part of the picture, self-tanner is simply a safer route to the same result.

Learn more in our guide to how self-tanning products work and what to know before using them.

FAQ

How many calories does an hour of sunbathing burn?

Sunbathing burns roughly 50 to 100 calories per hour for most adults, depending on body weight and individual metabolic rate. This is similar to what you’d burn lying on a sofa watching TV. It’s not a meaningful calorie-burning activity.

Does tanning burn belly fat specifically?

The University of Alberta study found that blue light from the sun affects subcutaneous fat cells — fat stored just beneath the skin. There may be some minor effect on fat near the surface of the abdomen. However, visceral fat (the deeper fat around your organs) sits too far below the surface for light to reach it, and researchers do not recommend sun exposure as a fat-loss strategy.

Do you burn more calories in a hot environment?

No — the opposite tends to be true. Your body burns more calories in cold conditions because it has to generate internal heat to stay warm. In a hot environment, that thermogenic demand drops, and overall calorie burn at rest is slightly reduced.

Does sweating while sunbathing mean you’re losing weight?

Not in any meaningful way. Sweat while sunbathing is your body’s response to external heat, not a sign of energy expenditure. Any weight lost through sweating in the sun is water weight, which returns the moment you drink fluids.

Can tanning help with weight loss?

Not as a primary method. There are some minor metabolic and fat-cell effects associated with UV and blue light exposure, but none are significant enough to contribute meaningfully to weight loss. The risks of UV overexposure — skin ageing and skin cancer — far outweigh any marginal benefit. Exercise, a healthy diet, and good sleep will all be far more effective.

Is red light therapy better than tanning for fat loss?

Red light therapy (photobiomodulation) has emerging research suggesting it may support fat reduction when combined with exercise, but it’s a different wavelength entirely from the blue light studied in the University of Alberta research. It also operates at much lower intensities than UV tanning. The evidence is promising but still developing — it shouldn’t be treated as a proven fat-loss treatment in isolation.

Conclusion

Tanning does burn calories, but only in the same way that any activity does — including sleeping. The real science lies elsewhere: sunlight’s blue light wavelengths may cause fat cells to hold less fat, and UV exposure has a mild stimulating effect on thyroid function and metabolism. These are genuinely interesting findings, but researchers are clear that they don’t translate into a weight-loss strategy.

Tanning beds offer similar minimal calorie burn but without the blue light that makes outdoor sun exposure mildly interesting from a fat-cell perspective. Self-tanning has no metabolic effect whatsoever — though it remains the safest way to get a tan.

If a bronze glow is the goal, tanning has plenty going for it. If weight loss is the goal, the usual advice still applies: move more, eat well, sleep enough. Lying in the sun is a lovely bonus, not a strategy.

References

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