Health briefs: Is cool-down needed after cardio workout?

Is a cool-down really necessary after a cardio workout?

"For a long time, the theory was that cooling down by continuing to exercise at a lower intensity would help the legs flush out lactate" and avoid soreness the next day, said Ross Tucker, a South African physiologist and a founder of the website the Science of Sport. "That's still dogma among many coaches and athletes."

But it's a myth. "We now know that lactate isn't responsible for muscle damage or soreness," Tucker said, and cooling down doesn't rid muscles of it anyway.

The available scientific evidence shows, in fact, little benefit from cooling down as most of us do it, with a prolonged, slow easing of physical effort.

Which is not to say that you should abruptly end a workout. During lengthy, strenuous exercise, blood vessels in your legs expand, and blood can pool there if you shift suddenly from high to zero exertion, resulting in dizziness or fainting. A few minutes of jogging, walking or other light exertion will normalize blood flow, Tucker said.

Federal forecasters calculated that for most of the Earth, last month was one of the hottest Marchs on record — except in the United States.

The National Oceanic and Atmospheric Administration said it was the fourth-hottest March in 135 years of records.

But in the United States, March was about a degree cooler than normal, or about a half a degree Celsius. It was the 43rd-coolest March on record.

Slovakia had its hottest March on record while South Korea and Latvia had their second warmest. Northern Siberia was 9 degrees (5 C) warmer than normal. Norway and Denmark averaged nearly 7 degrees (4 C) warmer than normal.

Despite recommended limits on codeine use in children, the potent painkiller is prescribed for them in at least half a million emergency room visits each year, a study suggests.

Use of the drug in that setting is hardly rampant — just 3 percent of kids' ER visits resulted in a codeine prescription in 2010, the 10-year study found. But with more than 25 million ER visits by children each year, the authors say far too many kids are getting the drug when better options are available.

Codeine is an opiate drug, and a genetic variation makes some people metabolize it too quickly, potentially resulting in dangerous side effects including excessive sleepiness and difficulty breathing. The Food and Drug Administration issued its strictest warning last year about a rare risk for life-threatening complications or death in children given the drug after certain surgeries.

Illegal fishing is a major concern of scientists because the world's oceans can barely sustain legal seafood harvests.

Earlier studies have shown that illegal and underreported fishing comprises up to 31 percent of the world's catch, but this study is the first to examine how much of it slips pass better-inspected U.S. ports.

"That was really a surprise to us," said Tony Pitcher, a professor of fisheries at the University of British Columbia who helped author the study. Americans ate about 2 million tons of seafood in 2011, second only to China.