Background
: Because blood pressure is changeable time to time, clinic blood pressure does not represent person's blood pressure and in determing of prognosis of hypertensive patient, 24 hours blood pressure is more important than clinic blood presure. Diurnal variation of blood pressure already was known in many study.
The object of this study was to investigate yhe diurnal variation of blood pressure in nomotension and hypertension.
Mothods : The subjects of nomotension was clinic systolic BP(measured more than one) less than 140 mmHg and diastolic BP less than 99mmHg and healthy. The subjects of hypertension was clinic systolic BP(mean measured more than three) less than 140mmHg and diastolic BP less than 90mmHg and no previous history of anti-hypertensive drugs.
24 hours blood pressures of two subjects was messured using noninvasive 24hours ambulatory blood pressure monitoring. And time interval was 1 hour.
All measurements was classified day-time and night-time, and day time was 7:00am~10:00pm, night time was 11:00pm~6:00am.

Results : The No. of subjects was 21 in normotension and 19 in hypertension. Mean age was 41±11 in hypertension. The mean blood pressure in normotension was 121±12mmHg/78±8mmHg in clinic, 111±10mmHg/72±12mmHg in 24hrs ambulatory, 118±14mmHg/76±11mmHg, and 98±14mmHg/64±11mmHg in night time The mean blood pressure in gypertension was 146±7mmHg/97±8mmHg in clinic, 136±17mmHg/86±12mmHg in 24hrs ambulatory, 141±15mmHg/89±9mmHg in day time, 124±17mmHg/76±11mmHg in night time. Dirunal variation of BP in hypertensive was likely to one in normotensives in graph. And the differences in diurnal variation of BP between two groups was signinificant in systolic BP(p<0.05) ; normotensive more than hypertesives) but not significant in diastolic BP(p>0.05). And the differences between clinic and 24hrs ambulatory BP in hypertensives was significant in systoli and diasyolic.(p<0.05 ; clinic more than 24hrs ambulatory)

Conclusion : Diurnal variation of BP in hypertensive was likely to one in normotensives in graph. From the result of the differences between clinic and 24hrs ambulatory BP in gypertensives was significant in systoli and diasyolic.(p<0.05 ; clinic more than 24hrs ambulatory), I think that in follow up BP of hypertension patients, 24hrs BP was more helpful than clinic BP. And from diurnal variation of BP in hypertensives, I think that further study is necessary in minitoring of anti-hypertensive drugs.