If you are watching your blood pressure (BP), chances are you pay more attention to the top number, the systolic blood pressure. But should you worry if the bottom number, the diastolic blood pressure, is high? The short answer is yes. If the bottom number is 90 mmHg or higher you may be considered to have hypertension. The good news is that you can work with your GP and adopt simple lifestyle changes that may help lower your diastolic blood pressure.
In this short article we explain more about diastolic blood pressure and why it matters. We also look at what causes high diastolic blood pressure and what you can do to lower your reading safely.
Systolic vs diastolic blood pressure
When you visit your GP and they take your blood pressure, two numbers are recorded, a top number and a bottom number, with the top number usually larger. Your GP will consider these numbers and advise whether your blood pressure is high, low, or within a healthy range. But do you know what these numbers represent?
The top, larger number is your systolic blood pressure. This is the highest pressure exerted by the heart on your arteries during a single beat.
The bottom, smaller number is your diastolic blood pressure. This is the pressure in the arteries between heart beats.
The systolic number often receives more attention, partly because a common type of hypertension involves a high systolic BP with a normal diastolic BP. However, it is important to keep a close eye on diastolic blood pressure too, especially if your number is creeping towards, or exceeding, 90 mmHg.
What is diastolic blood pressure?
As mentioned above, diastolic blood pressure measures the pressure in the arteries when the heart is at rest, between beats. During this time, the heart is refilling with oxygenated blood from the lungs.
While elevated systolic blood pressure is very common and historically received more attention, both numbers are important. Diastolic pressure can also indicate cardiovascular risk. Either an elevated systolic or diastolic reading can be used to diagnose high blood pressure.
Here is a simple way to interpret diastolic numbers commonly used in Australia:
- Optimal: below 80 mmHg
- Normal: below 84 mmHg
- High normal: 85 to 89 mmHg
- Hypertension: 90 mmHg or higher
If your diastolic pressure is 90 mmHg or higher and your systolic pressure is below 140 mmHg, this may be isolated diastolic hypertension (IDH). Speak with your GP for an assessment and personalised advice.
Why is diastolic blood pressure important?
Diastolic hypertension is associated with increased risks of cardiovascular disease, including stroke, coronary heart disease, heart failure, aneurysm, vision loss and kidney disease. Even when systolic pressure appears normal, elevated diastolic pressure can independently raise cardiovascular risk. Monitoring and early management are key.
What causes isolated diastolic hypertension?
Isolated diastolic hypertension can be associated with:
- Endocrine conditions that affect hormone production and regulation
- Renovascular conditions that affect blood flow to the kidneys
- Sleep apnoea, which is linked with elevated blood pressure and cardiovascular risk
Lifestyle factors can also play a role. Younger age, higher body mass index, and smoking are commonly associated with IDH. Keeping active, maintaining a healthy weight, and quitting smoking/ vaping are important steps for prevention and management.
Get expert tips on diastolic blood pressure and heart health, designed for Canadians over 50. Join the Aktiia Newsletter today for trusted advice.
Stress and diastolic blood pressure
When you experience stress, your body releases hormones that increase heart rate and narrow blood vessels. This can raise blood pressure. Chronic stress can also lead to behaviours such as overeating or smoking, which further contribute to high blood pressure. Techniques such as regular physical activity, meditation, breathing exercises, and good sleep habits can help.
For a comprehensive understanding of natural methods to control high blood pressure, you may find valuable insights and practical tips in our article, ‘How to lower high blood pressure naturally, without medication‘.
Risks of high diastolic blood pressure
High diastolic blood pressure increases the risk of heart attack and stroke because the heart must work harder against increased resistance in the arteries. Over time, this can damage blood vessels and organs.
Other risks include damage to the kidneys and eyes, peripheral artery disease, sexual dysfunction, and possible impacts on brain health. Managing blood pressure with lifestyle changes and medicines when appropriate can help reduce these risks.
Dementia and blood pressure
Research suggests a possible link between high blood pressure and an increased risk of dementia. High blood pressure can damage blood vessels and reduce blood flow to the brain, which may contribute to cognitive decline. Managing blood pressure through lifestyle and medicine can help reduce these risks.
How can you reduce diastolic blood pressure?
There are many things you can do to lower blood pressure overall. Your GP may recommend changes to your diet and lifestyle, and sometimes prescribe medicine.
If you only have high diastolic blood pressure, it is important to work closely with your GP so it does not drop too low. Diastolic pressure below 60 mmHg can reduce coronary blood flow to the heart muscle. Individual targets should be set by your clinician.
Tips to reduce blood pressure
Exercise regularly
Australian guidelines recommend at least 150 to 300 minutes of moderate-intensity physical activity each week, plus muscle strengthening on most days.
Eat for heart health
Follow the Heart Foundation’s heart healthy eating pattern and the Australian Dietary Guidelines.
Cut down on salt
High sodium intake is linked with hypertension. Choose products with the Health Star Rating and flavour foods with herbs and spices instead of salt.
Drink less alcohol
The NHMRC guidelines advise no more than 10 standard drinks per week and no more than 4 standard drinks on any one day.
Manage stress
Try walking, yoga, mindfulness, or spending time with friends and family. If stress affects your day-to-day life, seek help from your GP or a mental health professional.
Take medicines as prescribed
If your GP has prescribed blood pressure medicine, take it as directed.
Strategies to lower diastolic blood pressure naturally
Some complementary approaches may provide modest benefits as part of a broader plan:
- Omega 3 fatty acids from fish such as salmon and sardines support heart health
- Garlic may have small blood pressure effects in people with hypertension
- Herbal teas like hibiscus may assist modestly for some people
Always discuss supplements with your GP or pharmacist, especially if you take medicines, as interactions can occur.
Disclaimer: This article is for educational purposes only and is not medical advice. If you have health concerns, consult your GP or a qualified healthcare provider. Any lifestyle or medicine changes should be made under medical supervision.
Sources
Australian Government Department of Health and Aged Care. How Smoking Affects Your Body. https://www.health.gov.au/topics/smoking-vaping-and-tobacco (Accessed July 2025)
Australian Government Department of Health and Aged Care. Physical Activity and Sedentary Behaviour Guidelines for Adults (18 to 64 years). https://www.health.gov.au/topics/physical-activity-and-exercise/physical-activity-and-exercise-guidelines-for-all-australians (Accessed July 2025)
Australian Institute of Health and Welfare. High Blood Pressure. https://www.aihw.gov.au/reports/heart-stroke-vascular-diseases/hsvd-facts/contents/risk-factors/high-blood-pressure (Accessed July 2025)
Healthdirect Australia. High Blood Pressure (Hypertension). https://www.healthdirect.gov.au/high-blood-pressure-hypertension (Accessed July 2025)
Heart Foundation. Fats, oils and heart health https://www.heartfoundation.org.au/healthy-living/healthy-eating/fats-oils-and-heart-health?utm_source=chatgpt.com
(Accessed July 2025)
Heart Foundation. Heart-Healthy Eating Patterns. https://www.heartfoundation.org.au/healthy-living/healthy-eating/heart-healthy-eating-pattern (Accessed July 2025)
National Heart Foundation of Australia. Guideline for the Diagnosis and Management of Hypertension in Adults. https://www.heartfoundation.org.au/for-professionals/hypertension (Accessed July 2025)
National Health and Medical Research Council. Australian Guidelines to Reduce Health Risks from Drinking Alcohol. https://www.nhmrc.gov.au/health-advice/alcohol (Accessed July 2025)
National Health and Medical Research Council, Australian Government Department of Health and Aged Care. The Australian Dietary Guidelines. https://www.eatforhealth.gov.au/sites/default/files/2022-09/n55a_australian_dietary_guidelines_summary_131014_1.pdf (Accessed July 2025)
Siervo, M.; Lara, J.; Chowdhury, S. et al. (2015). Effects of the DASH diet on cardiovascular risk factors: a systematic review and meta-analysis.Br J Nutr, 113(1), 1–15. https://doi.org/10.1017/S0007114514003341
