Do stress balls work?

Does that stress ball collecting dust next to your laptop really work?
Believers say the squeeze-and-release motion in handling a stress ball relieves the tension we feel under duress, when we physically clench our muscles. It's supposed to help the user relax by releasing pent-up energy.
But researchers at the University of Wisconsin-Madison Department of Physiology found "no significant difference in stress alleviation between groups with or without a stress ball."
They monitored two groups, one that used stress balls and a control group that didn't, to check differences in heart rate, blood pressure, and cortisol levels — which tend to elevate when people are under stress — following "exposure to an exam-like situation."
The researchers said they focused on physiological reactions that could be measured, not whether the stress ball serves to provide moderate level muscular exertion or distraction from the impending task.
"Based on our results, we found that stress balls are ineffective at lowering some of the physiological measurements of stress," they said. "However, further studies of other stress-relief techniques would be greatly beneficial."
According to the American Psychological Association, the stress that comes from daily demands and pressures results in physiological changes that have a negative impact on cognitive thinking, including decision-making, working memory, reasoning ability, and other aspects of a person's personality and character.
Experts in stress relief agree that exercise, like a quick walk around the block during a work break, is a proven way to relieve the tension in your life.
Source: University of Wisconsin-Madison Department of Physiology: jass.neuro.wisc.edu.