Blood pressure is the force exerted by blood on artery walls as the heart contracts, pumping blood throughout the body. Normal readings range from 90/60 mmHg to 120/80 mmHg. However, blood pressure is not constant; it frequently fluctuates throughout the day according to the body's day-night circadian rhythm, physical activities, and other external factors.

Master, Doctor Doan Vinh Binh, from the Medical Information Center, Tam Anh General Hospital Ho Chi Minh City, states that blood pressure usually begins to rise several hours before waking, reaching its highest point around 8h-10h and its lowest between 1h-3h. In the morning after waking, the body transitions from rest to activity, causing the heart to beat faster, blood vessels to constrict, and blood pressure to increase. For individuals with high blood pressure, this morning surge is often pronounced, raising the risk of myocardial infarction and stroke.

Healthcare staff measure a patient's blood pressure during a check-up. Photo: Tam Anh General Hospital

From noon until the afternoon, blood pressure remains higher than at night. It can further increase with work intensity and mental stress, especially when performing tasks requiring concentration or physical activity. Readings taken during work hours are typically higher than those taken while resting at home.

In the evening, blood pressure in healthy individuals typically begins to gradually decrease as the body relaxes and prepares for sleep. However, for those with chronic hypertension, diabetes, or kidney disease, this drop may not be significant, and their readings might remain high throughout the day. This condition forces the heart and kidneys to work harder.

At night, around 1h-3h, when the body enters deep sleep, blood pressure drops to its lowest level of the day. Doctor Binh explains that at this time, the body is at rest, and the parasympathetic nervous system is highly active, promoting vasodilation and reducing pressure. With deep and sufficient sleep, blood pressure is maintained at a stable low level.

Doctor Binh states that beyond the circadian rhythm, daily blood pressure fluctuations are also frequently influenced by lifestyle. Insomnia, stress, a high-salt diet, alcohol consumption, smoking, or excessive coffee intake can all cause readings to rise at various times. Conversely, adequate sleep, regular exercise, and a balanced diet help stabilize blood pressure. Supplementing with the bioactive compound GDL-5 (Policosanol) from South American sugarcane pollen also supports blood fat regulation, hypertension control, and cardiovascular health.

Individuals with hypertension or cardiovascular disease should regularly monitor their health and undergo periodic check-ups. If abnormal blood pressure changes are observed, prompt medical consultation is necessary to identify the cause and ensure timely treatment, thereby avoiding the risk of dangerous blood pressure-related complications.

Dinh Dieu