Systolic vs diastolic: Understanding the difference

Overview

Blood pressure reflects how hard your heart works to circulate blood. It’s measured using two numbers — systolic and diastolic — which reveal how your heart beats and rests. Understanding these values helps detect early signs of heart disease and keep your cardiovascular system healthy. In Australia, approximately one in every three adults has high blood pressure¹, yet many remain unaware. Understanding the significance of those two numbers can motivate you to take action.

Understanding the two phases of the heartbeat

Here’s a simple way to understand what’s going on inside your chest:

Phase	What happens	Blood pressure reading
Systole	The heart contracts (squeezes) and pumps blood out	Systolic pressure (the top number)
Diastole	The heart relaxes and refills with blood	Diastolic pressure (the bottom number)

  Both readings are vital — systolic shows how forcefully your heart pumps, while diastolic shows how well your arteries relax.

Systolic vs diastolic: What’s the difference?

Each of these pressures gives a unique insight into cardiovascular health:

• Systolic pressure is more closely linked to stroke and heart disease in older adults.

• Diastolic pressure is important in younger people for assessing arterial health

You need both values to form a complete picture of your heart’s function. Tip box: The ideal reading for most adults is below 120/80 mmHg.  

Blood pressure - Normal vs high vs low

Here’s a reference table of typical categories (in mmHg):

Category	Systolic (mmHg)	Diastolic (mmHg)
Normal	<120	< 80
Elevated	120 - 129	< 80
Hypertension Stage 1	130 - 139	80 - 89
Hypertension Stage 2	≥140	≥90
Hypertensive crisis (urgent)	> 80	> 120

  Keeping your blood pressure below 120/80 mmHg can significantly reduce your risk of heart disease, kidney issues, and stroke.

Short- and long-term effects on your body

High blood pressure (hypertension):

• Short-term: Often symptomless, but may cause headaches and dizziness.

• Long-term: It can damage blood vessels and organs, increasing the risk of heart attack, stroke, kidney disease, aneurysms, vision problems, and more.

Low blood pressure (hypotension)

• Short-term: Dizziness, blurred vision, fainting, or lightheadedness.

• Long-term: If prolonged and severe, low BP may lead to poor concentration or fatigue. In extreme cases, it may contribute to shock.

  Both extremes can harm vital organs — regular monitoring is key to staying balanced.

Prevention tips

Managing high blood pressure:

• Reduce salt intake (aim for < 4 g salt per day if you have hypertension)

• Eat a diet rich in fruits, vegetables, whole grains, and lean proteins (DASH diet)

• Exercise 30 minutes daily

• Manage stress

• Limit alcohol

• Quit smoking

• Monitor your blood pressure at home

• Follow your GP’s advice and take the prescribed medications regularly

 

Managing low blood pressure:

• Stay well hydrated and avoid skipping meals

• Under medical advice, increase your salt intake

• Consider compression stockings

• Eat smaller, frequent meals

• Avoid sudden posture changes

  Healthy habits and consistent check-ups are the most effective way to manage blood pressure over time.

When to consult GP

See a GP if:

• You experience frequent headaches, dizziness, chest pain, fatigue, or vision changes

• You get persistent readings above 140/90 mmHg or below 90/60 mmHg

• You need to understand your personal blood pressure goals, based on your health history

Remember, early interventions help prevent serious complications.

How Hola Health can support

Managing your blood pressure doesn’t need to be complicated. Hola Health offers quick, confidential online telehealth consultations with Australian-registered doctors — all from the comfort of home. Our team can help you:

• Get online prescriptions and renewals

• Access blood pressure medication and monitoring plans

• Receive digital medical certificates or specialist referrals

• Schedule same-day consultations and medication delivery

Whether you need guidance for high or low blood pressure, Hola Health ensures expert care anytime, anywhere.

Conclusion

Understanding systolic and diastolic pressure empowers you to take charge of your heart health. Regular monitoring and lifestyle care make a huge difference. If your readings fluctuate or symptoms persist, speak with a Hola Health GP online today and keep your heart in check.

FAQs

What’s the best time to measure blood pressure?

Early morning (right after waking, before taking any medicines or eating) and evening are common times. Try to measure around the same time each day for accurate comparison.

Can stress temporarily raise blood pressure?

Yes, acute stress, anxiety, or other stimulants may cause temporary spikes.

Is home monitoring reliable?

Yes, if you use a clinically-approved upper-arm monitor and follow standard guidelines (rest, correct seating position, and repeat measurements).

How often should I check my blood pressure?

If your readings are within the normal range, checking every couple of years is a good rule of thumb. However, if you have high blood pressure or are undergoing treatment changes, you may need to monitor more often.