when a person mentions a felling of exhaustion while dowsing he has to rest for a while.i ve seen people ready to insensible after dowsing and i ve also seen rods ready to break while dowsing from the strength of the signal.however rods are difficult to get u exactly to the zero point because of the magnetic field of the object.its about the magnetic ring the object creates after years buried and thats why rods will lead u some metres away the zero point .hope i hepl