Stamina for slowmotion

I have this slowmotion javascript

#pragma strict

function Update()
{
	if(Input.GetButtonDown ("Fire1"))
	{
		if(Time.timeScale == 1.0)
		Time.timeScale = 0.3;
		
	else
	
		Time.timeScale = 1.0;
		Time.fixedDeltaTime = 0.02 * Time.timeScale;
	}
}

and I want something like stamina…
Can you help me?

To pause slomo set

Time.timeScale = 0;

And stop deducting time from the stamina bar.