Hypertension, known as the "invisible killer" of human health, long-term blood pressure control is not good, will damage blood vessels, heart, kidneys, brain, eyes and other important organs.
According to the Blue Book on the Prevention and Treatment of Hypertension in China 2018, from 2012 to 2019, the prevalence of hypertension in the adult population in mainland China has increased year by year, and about 1 in every 3 adults has hypertension.
In addition to well-known risk factors such as high salt, low fruit and vegetable intake, lack of exercise, smoking and alcohol consumption, ambient temperature has also been found to be strongly associated with high blood pressure.
So, what is going on when blood pressure becomes low during the day in summer and high at night? Is the lower the blood pressure value, the better?
Today, let's talk about blood pressure...
Blood pressure becomes lower during the day and higher at night in summer?
Previous research evidence suggests that controlling blood pressure can significantly reduce the morbidity and mortality of cardiovascular and cerebrovascular diseases.
The 2018 revised Guidelines for the Prevention and Treatment of Hypertension in China point out that 51.6% of patients with hypertension in mainland China know that they have hypertension, 45.8% of patients receive treatment, and only 16.8% of patients have their blood pressure controlled.
Epidemiological studies have shown that high temperatures increase hospitalization and mortality in patients with hypertension, with the elderly being the most pronounced group affected by high temperatures. Summer is the season of high incidence of cardiovascular and cerebrovascular events in elderly patients, which is significantly higher than that of spring and autumn, and the incidence is comparable to that of winter.
Whether male or female, age- individuals with normal blood pressure, or people with hypertension, blood pressure can exhibit seasonal variations, i.e., lower levels at higher ambient temperatures and higher at lower temperatures.
The reason for this may be due to:
1. In a cold environment, vasoconstriction and peripheral resistance increase, while in a warm environment, vasodilation and peripheral resistance decrease, making blood pressure decrease;
2. When the weather is hot, the evaporation of water in the human body increases, sweating increases, resulting in increased salt loss and decreased blood volume, which may further lead to a decrease in blood pressure in summer;
3. The decrease in ultraviolet intensity in winter is related to the decrease in vitamin D reserves and increased secretion of parathyroid hormone, which stimulates the growth of vascular smooth muscle and enhances its contractility by influencing intracellular calcium, epinephrine reactivity and/or endothelial function, while in summer it is the opposite;
4. Associated with the timing of sunlight exposure, it may be mediated by changes in melatonin affecting the secretion of epinephrine, corticosteroids and prolactin.
Previous studies have found that blood pressure during the day in summer drops by an average of 3 mmHg compared to winter. Especially in the elderly, it may be due to the decline in the body temperature regulation ability of the elderly, and it is difficult to adjust physiological compensation after heating, so there may be an excessive decrease in blood pressure in summer, and it is necessary to adjust the hypertension medication regimen.
However, if the drug is stopped on its own, it is likely that there will be a rebound increase in blood pressure again, resulting in aggravated vascular damage, and even adverse events such as stroke and angina.
Blood pressure may be higher at night than in winter. This may be due to the hot summer climate, long days and short nights, coupled with mosquito infestation, it is easy to have poor sleep quality and shorten sleep time, resulting in autonomic disorders and increased blood pressure at night. At this time, improper self-medication reduction in summer may lead to further uncontrollable blood pressure at night, increasing the risk of cardiovascular and cerebrovascular diseases.
Therefore, it is necessary to carefully adjust the medication under the guidance of the doctor to avoid repeated fluctuations in blood pressure.
Blood pressure value, the lower the better?
In fact, the lower the blood pressure value, the better.
On the one hand, the blood pressure value is too low, so that the whole body blood perfusion is insufficient, resulting in insufficient blood supply to important organ tissues such as cerebral arteries, coronary arteries, kidneys, etc., fatigue, fatigue, dizziness, memory loss, chest tightness, and severe cases can induce cerebrovascular accidents and angina, myocardial infarction, decreased kidney function, etc.;
On the other hand, postural hypotension may trigger a sudden fall in the elderly after getting up, and the elderly are often accompanied by osteoporosis, which often causes fractures after falling.
Therefore, for the elderly, the weight of antihypertensive is stable, and excessive antihypertensive is a kind of damage to our heart, brain, kidneys and other important organs.
Is it good that many people have high blood pressure but are not uncomfortable?
When it comes to high blood pressure, the first reaction is dizziness and headache. In fact, many people have high blood pressure but no symptoms. This may be due to the gradual development of tolerance during a slow rise in blood pressure, or as we age, our bodies decline and we are not sensitive to elevated blood pressure.
With or without symptoms, the damage of elevated blood pressure to vital organs such as blood vessels, heart, kidneys, brain, and eyes is persistent. The absence of symptoms makes it difficult for us to pay attention to this potential, long-term injury, and even some patients will choose to ignore and not treat.
Precautions for summer hypertension
Limit salt
High-salt diet is an important factor in the high blood pressure of the Chinese people, the World Health Organization recommends that the daily salt intake is not more than 5g / day, according to statistics, the intake of Chinese people can reach 12 to 14g, therefore, salt restriction is very necessary.
Home blood pressure monitoring
The easiest way is to measure it with a blood pressure monitor at home, choose 3 days morning and evening, measure blood pressure twice after a 5-minute break, 1 minute interval each time, and take the average. If the difference between the two arms is consistent> 10 mmHg, use an arm with higher blood pressure.
Typically, a family blood pressure ≥ 135/85 mmHg is diagnosed as hypertension.
For patients with blood pressure fluctuations in summer, it is more important to adhere to home blood pressure monitoring to observe changes in blood pressure, so as to provide reference and basis for adjusting the treatment plan.
Don't be cold in summer
The air-conditioned room temperature should be avoided too low (the indoor and outdoor temperature difference is preferably less than 8 ° C), avoid ingesting too many cold drinks, and avoid taking cold showers.
The alternation of hot and cold, "ice and fire double days" can easily lead to violent fluctuations in blood pressure. Suddenly entering the cold indoor from the hot outdoors or excessive consumption of cold drinks leads to rapid constriction of blood vessels, violent increase in blood pressure, and is prone to cerebrovascular accidents such as stroke.
In addition, there are several considerations:
Patients with high blood pressure should pay attention to avoid exercising in high temperatures in the summer.
In summer, pay attention to improving the quality of nighttime sleep, and you can also choose to restore your strength through lunch break.
Pay attention to hydration and do not wait for thirst before drinking water. Because of the evaporation and sweating of water in summer, body fluids are reduced and blood is more viscous, which can be corrected by hydration.
Expert: Zhang Honghong, Department of Cardiology, General Hospital of the People's Liberation Army of Chinese, graduate student
This article was reviewed by Li Jiehui, Deputy Chief Physician, Department of Cardiac Surgery, Fuwai Hospital, Chinese Academy of Medical Sciences
(Popular Science China)