Final answer:
An elevated pulse in a 21-year-old male post-exercise is typically due to physical exertion and is generally not concerning unless accompanied by other symptoms. Low blood pressure with confusion and thirst could suggest shock, and increased heart rate on standing is often a response to orthostatic changes.
Step-by-step explanation:
The question is about assessing the clinical significance of an elevated pulse in a 21-year-old male. Given the information that the patient was just running, the elevated pulse is likely due to physical exertion. When a person exercises, the body requires more oxygen and nutrients, which is achieved by increasing the heart rate to pump more blood to the working muscles. This is a normal physiological response and would not generally be concerning in a healthy individual unless the pulse remains inappropriately high for an extended period after stopping exercise or is accompanied by other symptoms.
In contrast to this scenario, a patient with a blood pressure of 70/45 who is confused and complaining of thirst could be experiencing shock, possibly due to dehydration or other causes, which is a medical emergency. Similarly, a change in position from lying down to sitting to standing can cause orthostatic hypotension, where the heart rate increases to maintain blood pressure and circulation in response to gravity's effects on blood distribution.