But the results of the trials of that drug, known as VX-809, were less positive, showing improvements in lung function, but not in how much chloride is in sweat.

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In Left 4 Dead, test subjects had their sweat monitored, with values assigned to how much they were responding to the action.

ENGADGET

More research will be needed, but it could be that the sum total of how much movement we get throughout the day means more than whether we break a sweat for a shorter period.

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