How would you tie a keypress to a fill amount?

I have my health set to decrease every second by 5. I would rather be able to increase and decrease it as needed by pressing one button to replenish my health and another to subtract from it. Any suggestions?

void FixedUpdate()
{

      if( Input.GetKeyUp(KeyCode.Space)
         {
    
            currhealth -= dynamicRobustVariable;  
    
    
         }
    
       if (Input.GetKey("B"))
         {
              currhealth += dynamicRobustVariable;  
          }
}

Changed it for you. Much less fancy. I would check out the input doc on unity’s website for more key’s to use. GetKey fires on key press, where GetKeyDown fires when the key is held down, etc.