阅读理解
The weather is getting hotter and you'll be getting thirstier playing basketball or riding home from school. A cold drink may be just the thing. But be careful what you pour down your throat. Something that looks cool may not be good for your health.
There are plenty of so-called energy drinks (功能饮料) on the market. Most of them have an attractive color and cool name. Their nutrition (营养) lists also contain various things from vitamins to ginseng (人参). Sounds great!
But after a careful check you may find that most energy drinks contain high levels of caffeine (咖啡因). These drinks are typically (典型地) aimed at young people, students, busy people and sports players.
Makers sometimes say their drinks make you better at sports and can keep you awake. But be careful not to drink too much.
Caffeine raises your heartbeats (脉搏，心跳). Because of this, the International Olympic Committee has limited their use. The amount of caffeine in most energy drinks is at least as high as in a strong cup of coffee or strong tea.
Research by Australian scientists has found that many teenagers are affected by caffeine. The result of their survey show that 27 percent of boys aged 8--12 take in more caffeine than their parents.
There are potential (可能的, 潜在的) health risks (风险) linked to energy drinks. Just one can of energy drink can make you nervous, have difficulty sleeping and can even cause heart attacks.
Teenagers should be discouraged from having drinks with a lot of caffeine in them, an expert from the Australia Nutrition Foundation said.