Harvard Health Content API

In 2024, the FDA advised against using smart watches or smart rings that claim to monitor blood sugar without piercing the skin. Using them, the FDA warned, could result in inaccurate blood sugar measurements, which is dangerous for people with diabetes.

Paroxysmal supraventricular tachycardia is caused by an electrical glitch in the heart’s upper chamber that causes the heart rate to suddenly soar for no apparent reason—sometimes as high as 200 beats per minute. The condition, which people describe as palpitations or a fluttering sensation in the chest, is usually not dangerous. But long-lasting bouts can lead to lightheadedness, breathlessness, and fainting.

In addition to the Mediterranean diet, other European eating patterns—namely, the Nordic diet and the Atlantic diet—feature heart-healthy fare. All three diets feature seafood, vegetables, fruits, whole grains, legumes, and nuts, with an emphasis on seasonal and local foods. Such foods also support environmental health and sustainability. People in the United States can follow this trend by shopping at a farmer’s market or joining a community-supported agriculture program.

High-dose niacin (vitamin B₃) is no longer recommended to improve cholesterol and triglyceride levels. Different forms of niacin, such as niacinamide (nicotinamide), are sold as supplements; the potential benefits and risks remain unclear.

High-intensity interval training (HIIT) is a time-efficient way for people to improve their fitness and cardiovascular health. Even short bursts of high-intensity activity may trigger the release of mood-boosting brain chemicals. Traditionally, HIIT features 30 to 90 seconds of high-intensity effort followed by an equal or longer period of lower-intensity activity or rest. HIIT variations include fartlek (Swedish for “speed play”), which uses environmental cues to set intervals, and Tabata, which features 20-second intervals of intensity followed by 10-second recovery intervals.