Health Claims

In diabetic rats, running on a treadmill helps the heart relax better than lifting weights—even though lifting weights lowers blood sugar more.

Descriptive

When diabetic rats get regular cardio exercise, their heart muscle becomes more flexible and less stiff because they make more of a spring-like protein (titin) and less of the scar-like proteins (collagen and TGFβ1), which helps their hearts fill with blood better.

Correlational

If you only get three hours of sleep for two nights in a row, your face might look duller and less vibrant—like your skin lost its glow.

Correlational

If healthy women between 30 and 55 only sleep 3 hours a night for two nights in a row, their skin shows more signs of cellular damage from stress—like rust forming on metal—because a chemical called malondialdehyde goes up.

Correlational

If you only sleep 3 hours a night for two nights in a row, your skin might look duller, feel drier, and age faster because your body can’t repair itself properly while you’re sleep-deprived.

Correlational

When people use sunscreen heavily, tiny amounts of its chemicals—avobenzone and oxybenzone—can get into their blood, and scientists can measure these tiny amounts, though they’re way too small to see or feel.

Descriptive

When young and older men do short, super-intense bike or sprint workouts, the young guys get better at using oxygen during exercise, but the older guys don’t — their bodies just don’t respond the same way.

Descriptive

After a super intense sprint workout, your body releases a tiny bit of DNA into your blood — and the more tired your muscles feel afterward, the more DNA shows up. This could mean that measuring this DNA helps doctors tell how hard your muscles were pushed.

Correlational

Older men in their 60s and 70s didn’t get better at using oxygen during exercise after three weeks of intense sprinting, but younger men did—so aging might make it harder for your body to improve aerobic fitness from short, intense workouts.

Causal

After just three weeks of short, intense bike or sprint workouts, older men between 63 and 72 got better at bouncing back from muscle tiredness caused by repeated hard exercise — their muscles recovered faster and felt stronger afterward.

Correlational

After just three weeks of short, intense bursts of running, older men had less of a biological marker in their blood that signals stress or damage in the body—this might mean their bodies are under less strain as they age.

Correlational

Using sunscreen that blocks both UVA and UVB rays cuts sun damage in half, and adding antioxidants like vitamin C makes it even better.

Quantitative

Putting vitamin C on your skin or eating foods rich in vitamins C and E can help reduce wrinkles and dark spots caused by sun damage.

Descriptive

Taking a mix of antioxidant vitamins and minerals by mouth may help your skin resist sunburn and look better over time, but taking just beta-carotene alone doesn’t seem to stop skin aging from the sun.

Correlational

Showing adults pictures of how UV rays damage their skin or using phone apps that track sun exposure can help them feel more motivated to wear sunscreen and avoid too much sun—though the boost isn’t huge.

Correlational

Eating tomatoes and carrots (which have red and orange pigments) can help reduce sunburn and skin damage from the sun.

Descriptive

Sunscreen that also has extra ingredients like vitamin C or plant extracts that calm and repair your skin works better at reducing sun damage and wrinkles than sunscreen with just the basic sun-blocking chemicals.

Causal

Certain plant extracts, like green tea and grape seed, can help protect skin from sun damage by reducing harmful chemicals and inflammation caused by UV rays.

Descriptive

Your skin naturally has protective molecules that fight sun damage, but too much sun uses them up, leaving your skin more vulnerable to aging.

Descriptive

If you use sunscreen every day for a few months to a year, your skin might look smoother, have fewer dark spots, and show fewer wrinkles over time.

Correlational

If you put on sunscreen every single day for nearly five years, your skin will show about a quarter fewer wrinkles and sun spots than if you only use it sometimes.

Correlational

Sunlight, especially UV rays, creates harmful molecules in your skin that break down collagen, making your skin wrinkle and sag over time.

Mechanistic

If middle-aged women lift weights, it lowers certain body chemicals that cause inflammation, but if they do cardio like walking or cycling, it lowers different inflammation chemicals instead—so the kind of exercise you do changes which inflammation signals go down.

Causal

Different kinds of exercise help your skin in different ways: lifting weights boosts certain skin-building molecules, while cardio boosts others—so your skin might get healthier in unique ways depending on whether you lift or run.

Mechanistic