Hidden field - cast

I have a web user control in an aspx page.
I want to access a hidden field that is in the web user control.
To access a value from TextBox I do following in code behind of the aspx page:
TextBox h=(TextBox)MyWUC1.FindControl("TextBox1");
string myText = Convert.ToString(h.Text);

How would I get the value from a hidden inputfield that is in the web user control?
If I try following:

HiddenField h = (HiddenField)ProjectSubjectAgeWUC1.FindControl("hidText");

Then I get following error: Unable to cast object of type 'System.Web.UI.HtmlControls.HtmlInputHidden' to type 'System.Web.UI.WebControls.HiddenField'.