Dr. XXXXXXX is currently unavailable. Therefore let me take this opportunity to answer your question.Hypertension
or high blood pressure
most often occur due to known causes. It may be secondary to body genetic framework. In some cases heredity is hypothetised as the cause. In other occasion it occurs secondary to hyperthyroid, medications, renal artery
problems, endocrine disturbances and so on.
That being said, the blood pressure changes that you noted here are normal physiological changes which can occur with every man. You should not be concerned unless blood pressure readings are consistently high above 140/90mmHg on different occasions of week.
Nevertheless at your age, I will recommend you take a low salt diet and keep yourself active with physical exercise.
Hope this helps. Let me know if you need clarifications.