美国有线新闻 CNN 全球有11亿高血压 美国东南部山火肆虐（在线收听）

AZUZ: Scientists said Imperial College London recently studied world blood pressure statistics between 1975 and 2015, and here's what they found: 1.13 billion people, more than 15 percent of the world's population now have high blood pressure. That's almost twice the number of people affected 40 years ago, but this is also because the world population has increased in the last 40 years and gotten older. Those with higher blood pressure today tend to live in poorer parts of the world.

What causes elevated blood pressure? Lots of salt and potassium in diets, pollution and exposure to lead, and bad nutrition in childhood.

High blood pressure can increase your risk of strokes, heart, and kidney disease. But blood pressures aren't rising everywhere. Rates have dropped in the U.S. and Canada. Experts say better food options and health services have helped.

The drought in the U.S. southeast has contributed to the spread of dozens of wildfires. The U.S. Forest Service says more than 30 large fires have scorched more than 80,000 acres. That's like 80,000 football fields in Alabama, Georgia, Kentucky, North and South Carolina, and Tennessee.

But that's just the big fires. Yesterday, there were more than 67 total fires burning in Tennessee alone. There are states of emergency in several places hundreds of people have been hospitalized in Tennessee with breathing problems related to the fires.