Researchers say that gaining weight and losing hair may actually be signs of a lengthy lifespan for you.
According to Dr Martin Surks and colleagues at the Montefiore Medical Center and the Albert Einstein College of Medicine in New York, low thyroid activity may hold the key to a long life.
Located in the neck, thyroid is a kind of master gland, secreting hormones that affect metabolism. Its activity is usually checked by an indirect measure - looking at levels of TSH, or thyroid stimulating hormone.
High TSH levels suggest the thyroid is underactive, a condition known as hypothyroidism. Low levels suggest it is overactive, known as hyperthyroidism.
People with low thyroid function may lose hair, gain weight and feel sluggish, while those with overactive thyroids may lose weight, feel their hearts race and have trembling hands.
To reach the conclusion, researchers studied hundreds of people who had lived to be 100, and found evidence that people with low thyroid activity were more likely to be in that group, reports The China Daily.
"We studied a large group of Ashkenazi Jews with exceptional longevity," Surks told a news conference at a meeting of the Endocrine Society, specialists in human hormones.
Surks and colleagues found 15 to 20 percent of people over the age of 60 had TSH levels that suggest an underactive thyroid gland.