Normal blood pressure is below 120/80 mmHg, but it can drop too low. Blood pressure under 90/60 mmHg is classified as hypotension by the National Heart, Lung, and Blood Institute. Between those two numbers lies a wide range that’s perfectly healthy for most people, and the “right” target depends on your age, health status, and whether you’re taking medication.
What the Guidelines Define as Normal
The 2025 joint guidelines from the American Heart Association and American College of Cardiology break blood pressure into four categories:
- Normal: below 120/80 mmHg
- Elevated: 120 to 129 systolic (top number) with diastolic (bottom number) still under 80
- Stage 1 hypertension: 130 to 139 systolic or 80 to 89 diastolic
- Stage 2 hypertension: 140 or higher systolic, or 90 or higher diastolic
So the official “normal” range has no lower cutoff. A reading of 105/65 is just as normal as 118/78. Many people walk around with systolic pressures in the low 100s or even 90s and feel perfectly fine. The number itself only matters when it starts causing symptoms or falling below the thresholds where your organs can’t get enough blood flow.
When Low Becomes Too Low
The clinical definition of low blood pressure is anything below 90/60 mmHg. But that number is a rough guide, not a hard line. Some people, particularly younger women and athletes, live comfortably at 90/58 with no issues. What matters more than the number on the cuff is whether you’re experiencing dizziness, lightheadedness, blurred vision, nausea, fatigue, or fainting.
Your body needs a minimum average pressure (called mean arterial pressure) of about 60 mmHg to push blood through your brain, kidneys, and other vital organs. If pressure drops below that level for more than a short time, tissues start losing oxygen. The brain is especially vulnerable: a significant drop can cause loss of consciousness and, if sustained, permanent damage. Your body has built-in reflexes to prevent this, including speeding up your heart rate and tightening blood vessels, but those mechanisms can be overwhelmed by dehydration, blood loss, severe infection, or medication effects.
The Bottom Number Deserves Extra Attention
Most conversations about blood pressure focus on the top number (systolic), but research shows the bottom number (diastolic) has its own danger zone. A study published in The Journal of Clinical Hypertension found that people with diastolic pressure below 60 mmHg had a 30% higher risk of death from any cause compared to those in the 70 to 80 range, even when their systolic pressure was normal. The risk was especially pronounced below 50 mmHg.
This pattern, sometimes called the J-curve, means that pushing blood pressure lower isn’t always better. There’s a sweet spot. For most adults, a diastolic reading between 60 and 80 appears to carry the lowest risk. This is particularly relevant if you’re on blood pressure medication and your bottom number keeps dropping while your doctor focuses on bringing the top number down.
Targets Change With Age
For adults under 65, the general target is below 130/80 mmHg. But recommendations diverge for older adults, and the disagreement among medical organizations is worth understanding.
The 2017 AHA/ACC guidelines recommend targeting below 130/80 even after age 65. European guidelines from 2018 suggest a more relaxed target of below 140/90 for people over 65. And the American College of Physicians has recommended below 150/90 for some older populations. These aren’t small differences. They reflect a genuine tension in the evidence: lowering blood pressure reduces stroke and heart attack risk, but in older adults, going too low increases the risk of falls, fainting, kidney problems, and cognitive decline.
For people over 80 who are relatively healthy and independent, a systolic target below 140 is reasonable. For those who are frail, have dementia, or depend on others for daily activities, experts suggest keeping systolic pressure between 130 and 150 and reducing or stopping blood pressure medications if readings drop below 130. Orthostatic hypotension, a sudden drop in pressure when standing, is a particular concern in this group because it leads to falls and fractures.
Blood Pressure During Pregnancy
Pregnancy naturally lowers blood pressure, especially during the first and second trimesters. In a large prospective study, the average blood pressure for first-time mothers at 12 weeks was about 112/65, and it dipped further to its lowest point around weeks 17 to 20 before gradually climbing back up toward delivery. By 37 weeks, the average was roughly 116/70.
This mid-pregnancy dip is normal and happens because blood vessels relax to accommodate the increased blood volume of pregnancy. Readings in the low 100s systolic or upper 50s diastolic during the second trimester are common. Concern typically arises on the high end (140/90 or above after 20 weeks signals a hypertensive disorder) rather than the low end, though symptoms like persistent dizziness or fainting should still be evaluated.
Medications That Push Pressure Too Low
If you’re on blood pressure medication and feeling dizzy or lightheaded, the medication itself may be driving your numbers below your body’s comfort zone. Certain drug classes carry a higher risk of this than others.
The highest-risk medications for causing pressure drops, especially when standing, include alpha-blockers (often prescribed for prostate problems), nitrates (used for chest pain), antipsychotics, and Parkinson’s medications. Diuretics (water pills) and beta-blockers carry intermediate risk. Common antidepressants, including older tricyclics, certain sleep aids, benzodiazepines, and opioid pain medications also lower blood pressure as a side effect.
The risk compounds when you take more than one of these at the same time. If you’re on multiple medications and notice symptoms when you stand up, that combination is worth discussing with whoever prescribes them. Orthostatic hypotension is formally defined as a drop of at least 20 mmHg systolic or 10 mmHg diastolic within three minutes of standing, and it’s one of the most common medication-related problems in older adults.
What “Too Low” Feels Like
Blood pressure that’s too low for your body doesn’t always announce itself with a dramatic fainting spell. The early signs are subtler: feeling lightheaded when you stand up, difficulty concentrating, unusual fatigue, blurry vision, or a vague sense of “not feeling right.” You might notice cold or clammy skin, or that you feel significantly worse when you’re dehydrated or haven’t eaten.
More serious drops produce nausea, confusion, rapid shallow breathing, and a weak or fast pulse. Fainting is the body’s last-resort mechanism to get you horizontal so blood can reach the brain more easily. If someone loses consciousness from low blood pressure and doesn’t recover quickly after lying flat, that’s a medical emergency.
The Practical Takeaway
For most adults, the ideal blood pressure is below 120/80, with the bottom number staying above 60. There is no single “perfect” number. A reading of 110/70 is excellent for a 35-year-old but might be too aggressive a target for an 85-year-old on three medications. The best blood pressure is the lowest one that keeps your organs well-supplied with blood and leaves you feeling good on your feet, not just good on paper.