A study involving over 40,000 people found that seasonal changes directly impact blood pressure. Blood pressure generally improves in summer and decreases in winter, regardless of climate or altitude.
- Decreases in temperature activate the sympathetic nervous system, increase renin-angiotensin activity, and elevate blood pressure.
- Increases in temperature cause blood vessel expansion, vascular resistance reduction, and reduced blood volume. (BPinControl, 2023)
A study found that blood pressure readings were higher in winter than in summer in all cities studied, suggesting that the fluctuations in blood pressure are not related to a marked swing from hot to cold temperatures.
Instead, researchers speculate that the higher winter blood pressure may be related to shorter days, less activity, or weight gain during the winter months, or factors that remain unknown. (Halonen et al., 2010)
IMPACT OF COLD WEATHER
Cold weather can raise blood pressure, but it's important to avoid sudden increases by dressing in layers, covering your skin, acclimating gradually, and avoiding strenuous activities.
One underlying factor may be tied to changes in blood vessel diameter, as blood vessels shrink when they cool down, which may contribute to a slight increase in blood pressure over time.
Winter weather affects blood pressures through both systolic and diastolic pressures. Cold weather causes a surge in blood pressure, especially during morning hours. (Xu et al., 2019)
The body generates heat through food cravings and increased sugar and salt intake, leading to physical inactivity and potential winter hypertension.
Hypertensive patients face increased risks of cardiovascular incidents, particularly during cold morning hours, including stroke, sudden cardiac death, and acute myocardial infarction. The risk of hypothermia is greater during winter as the heart pumps harder to maintain a stable body temperature, leading to heart muscle damage. (Mpemwangi., 2021)
IMPACT OF HOT WEATHER
High temperatures and humidity can trigger health problems, especially for those with high blood pressure and heart disease. High temperatures and humidity can cause more blood flow to the skin, causing the heart to beat faster and circulating twice as much blood per minute.
The greatest risks occur when temperatures are above 70 degrees and humidity is over 70%. High humidity can affect those over 50, overweight, or have heart, lung, or kidney conditions.
Heat and sweating can also lower fluid levels, leading to dehydration, which can interfere with cooling off and strain the heart. Dehydration can lead to serious complications, especially for those at greater risk due to age, chronic conditions, or outdoor activities. (Halonen et al., 2010)
Warmer climates may encourage lower blood pressures, but fluctuations in blood pressure change quickly if one moves from a warmer climate to a colder one and more slowly if one moves from a colder climate to a warmer one.
Hot weather and prolonged sun exposure can lead to dehydration, increased body temperature, and increased cardiovascular risk. This can result in dehydration, faster heartbeat, and fluid loss. Heat also increases the risk of heart failure and stroke. (Xu et al., 2019)
Summer heat increases the risk of hypertension in hypertensive patients, leading to weakened pulse, inability to sweat, muscle cramps, hemoconcentration, and thrombosis.
- Preventive measures include staying hydrated by consuming high-water content foods and fruits, avoiding the mid-day sun, and exercising correctly.
- To stay hydrated, consume foods and fruits with high water content, such as cucumbers and watermelon.
- Avoid going outdoors during the peak sun hours, between noon and 4:00 p.m., to prevent cardiac workload. (BPinControl, 2023)
- Exercise indoors or during early morning or evening hours, ensuring adequate water intake.
- Hydration during workouts, and wearing breathable clothing to prevent overexertion.
- Cold protective measures include adding layers of clothes and using heating equipment.
- Targeted public health advice on clothing and outdoor activities is needed. Alcohol users should be reminded of temperature changes during health education or intervention.(Mpemwangi., 2021)
To reduce the adverse effects related to weather fluctuations on blood pressure, it is important to avoid overexertion, maintain a stable body temperature by wearing warm clothes, and take care against the flu. Overheating can cause an abrupt drop in blood pressure, while the flu can trigger blood pressure levels and related cardiovascular diseases. It is also important to avoid dehydration, which can lead to faster heartbeats to maintain steady blood pressure, potentially leading to winter hypertension.
The Impact of Weather on Blood Pressure | BPinControl. (n.d.). Retrieved November 2, 2023, from https://bpincontrol.in/stress-busters-for-high-blood-pressure/impact-of-weather-on-blood-pressure
Halonen, J. I., Zanobetti, A., Sparrow, D., Vokonas, P. S., & Schwartz, J. (2010). Relationship between outdoor temperature and blood pressure. Occupational and Environmental Medicine, 68(4), 296–301. https://doi.org/10.1136/oem.2010.056507
Xu, D., Zhang, Y., Wang, B., Yang, H., Ban, J., Liu, F., & Li, T. (2019). Acute effects of temperature exposure on blood pressure: An hourly level panel study. Environment International, 124, 493–500. https://doi.org/10.1016/j.envint.2019.01.045
Mpemwangi, H. (2021, July 23). Hot weather and blood pressure, heart. Mayo Clinic Health System. https://www.mayoclinichealthsystem.org/hometown-health/speaking-of-health/effects-of-high-temperatures-on-blood-pressure-heart