Staying Healthy Archive

What the latest science says about caffeine's influence on your heart, memory, sex life, and exercise performance.

Americans are jolted with caffeine. On average, about 80% of adults take some form of caffeine every day, according to the FDA, usually from coffee, tea, soda, or energy drinks.

But does all that caffeine have any effect on your health — either good or bad? "While caffeine can give you a temporary mental and physical boost, its impact depends on how much you consume and the source," says Dr. Stephen Juraschek, an internal medicine specialist at Harvard-affiliated Beth Israel Deaconess Medical Center.

You can do an all-around workout in just five minutes if you focus on intensity and target the main muscle groups.

Growing evidence continues to show that high-intensity interval training (HIIT) offers similar — or in some cases even superior — results compared with longer, lower-intensity workouts. With HIIT, you exercise for a short burst at near-maximum effort followed by a brief rest period, and then you continue to repeat the cycle over the next 10 to 15 minutes.

Small workouts, big gains

The main advantage to HIIT is that it takes less time than the traditional workout of 20 to 30 minutes or longer.

Here's what you can do about the three most common foot issues related to aging.

When our feet hurt, we hurt all over. That saying is often attributed to the Greek philosopher Socrates, and it's as relevant today as it was more than 2,500 years ago.

"Our feet are our vehicle to an active lifestyle," says Dr. Christopher DiGiovanni, chief of the Foot and Ankle Service at Harvard-affiliated Massachusetts General Hospital and Newton Wellesley Hospital. "If your feet are not sound and healthy, it's tough to keep the rest of you healthy, too."

In the journals

Zinc oxide (ZO) is one of the most effective ingredients in sunscreen, but previous studies have suggested it could potentially damage skin cells. Now, a small study in the February 2019 Journal of Investigative Dermatology has found that ZO nanoparticles don't penetrate the skin or damage skin on a cellular level even with repeated applications.

ZO is one of 17 active sunscreen ingredients approved by the FDA. ZO offers broad-spectrum protection and shields against both UVB rays, which cause sunburn, and UVA rays, which penetrate more deeply and are more likely to damage cell DNA and increase the risk of skin cancer.

In the journals

Spinach is one of the best sources for the antioxidant lutein, which may promote eye health and reduce the risk of macular degeneration. A new study in the March 30, 2019, issue of Food Chemistry suggests that eating uncooked chopped spinach can ensure you get the highest amounts compared with traditional cooking methods.

The researchers measured the lutein content of baby spinach after it was fried, boiled, and steamed. They found that lutein levels dropped by 40% after only four minutes of boiling, and by 90% after 90 minutes, while levels decreased by more than 60% after just two minutes of frying. Spinach lost about 50% of its lutein after four minutes of steaming.

Microneedling was once viewed with skepticism, but it can be an effective procedure to improve the skin.

If the idea of poking yourself in the face with tiny needles in hopes of improving your skin sounds a little bizarre to you, you're not alone. For years, the medical establishment looked at the practice, known as microneedling, with a leery side-eye.

"I didn't take it seriously until relatively recently," says Dr. Kenneth Arndt, medical editor of the Harvard Special Health Report Skin Care and Repair and a founding editorial board member of the Harvard Health Letter.

The answer to that question is becoming clearer, thanks to new research.

Some 10% of American adults regularly take an omega-3 supplement, despite uncertainty about whether these products truly live up to their health claims. But two new studies published in November 2018 shed some light on who might benefit from omega-3 supplements — and who probably won't.

VITAL

The first study was the Vitamin D and Omega-3 Trial (VITAL), a large multiyear study with 25,871 healthy adults with no history of cardiovascular (heart or blood vessel–related) disease and at "usual risk" for it. The group was racially diverse and chosen to be representative of the general population, says the study's lead author Dr. JoAnn E. Manson, professor of medicine and the Michael and Lee Bell Professor of Women's Health at Harvard Medical School.

Research we're watching

An ongoing lack of sleep may lead to more fatty buildup in the arteries, according to a study in the January issue of the Journal of the American College of Cardiology. Researchers measured the sleep quality of 3,974 people with no history of heart disease.

Participants wore a sleep monitor for seven days and were then categorized based how much they slept: short sleep (six to seven hours a night), reference sleep (seven to eight hours a night) and long sleep (more than eight hours a night). Study authors also looked at how fragmented participants' sleep was throughout the nights. They then compared those findings to measures of arterial buildup in the heart and other parts of the body.

There are many types of yoga. One of the most popular forms practiced in the United States is known as hatha yoga, a style that focuses on maintaining specific poses. What sets yoga apart from most other exercise programs is that it places as great an emphasis on mental fitness as on physical fitness, what's known as the mind-body connection.

Studies suggest that yoga has benefits for people with Chronic Fatigue Syndrome (CFS), arthritis, fibromyalgia, migraines, low back pain, and many other types of chronic pain conditions. It can also improve mood, which can be helpful to people with CFS who are depressed.