While Loop Not Working - - Please Help

Can someone please tell me why my while loop isn't working in this function?

const int ledPin = 13;
const int targetRelay = A0;
const int vibrationSensorPin = A6;

int threshold = 50;
int startTime = 0;
int settleTime = 2500;
int sensorReading = 0;

void feelProgram()
{
digitalWrite(ledPin, HIGH);
digitalWrite(targetRelay, HIGH);
while (startTime != settleTime)
{
delayMicroseconds(1000);
settleTime--;
if (startTime == settleTime)
{
break;
}
}
int sensorReading = analogRead(vibrationSensorPin);
if (sensorReading <= threshold)
{
digitalWrite(ledPin, LOW);
digitalWrite(targetRelay, LOW);
Serial.println(sensorReading);
sensorReading = 0;
regDelay(2500);
settleTime = 2500;
}
}

I agree with @Delta_G

As a programming exercise I would like make some comments on this bit

while (startTime != settleTime) // this would be better as while(starteTime > settleTime)
    {
    delayMicroseconds(1000);
    settleTime--;
    if (startTime == settleTime) // this IF is quite unnecessary. The WHILE clause will make this happen
      {
      break;
      }
    }

...R

Ah, sorry. I meant that it's skipping over my while loop and performing like it's not even there. I'm trying to set up a countdown timer to decrement and the code after is only allowed to execute when the while loop timer is expired.