阅读下列短文,从每题所给的A、B、C、D四个选项中, 选出最佳选项。
A
If you’re training for a marathon , a proper plan for water intake (摄入) is important. Of course, there’s the risk of dehydration (脱水). But athletes now know they can also get into trouble by drinking too much. Too much water intake can lower levels of sodium (钠) in the blood . The death of a 28-year-old woman following the Boston Marathon caught the attention of many runners and led to new research.
Experts advise long distance runners to replace the liquids they sweat out. Their goal is to try to keep someone from not getting dehydrated by more than 2 percent of their body weight.
One technique for deciding how much water you need is to get the exact numbers. Runners have to weight themselves before and after a run to determine how much water they’ve lost. If their weight drops by more than 2 percent, they have not drunk enough water.