🩺 Health & WellnessLast updated March 29, 2026

Blood Health & Vitals Guide: Blood Pressure, Blood Type & Body Metrics

Understand your vital signs and body measurements for better health

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BP Categories

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Key Takeaways

Normal blood pressure is below 120/80 mmHg — elevated is 120-129/<80, hypertension starts at 130/80.
Blood type is determined by A/B antigens and Rh factor — O- is the universal donor, AB+ is the universal recipient.
Body Surface Area (BSA) is used for drug dosing and burn assessment: BSA = √(height × weight / 3600) (Mosteller formula).
BAC of 0.08% is the legal limit in the US — one standard drink raises BAC by ~0.015-0.02% per hour.

Your blood health and vital signs are the most direct indicators of overall wellness. This guide — based on American Heart Association guidelines and Red Cross blood type information — explains how to interpret key health metrics with our free blood pressure calculator.

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Understanding Blood Pressure

Blood pressure measures the force of blood against artery walls. Systolic (top number) measures pressure during heartbeats; diastolic (bottom) measures pressure between beats. The AHA blood pressure categories range from Normal (<120/80) to Hypertensive Crisis (180+/120+). Track yours with our blood pressure calculator.

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Blood Type Compatibility

There are 8 main blood types based on A/B antigens and Rh factor: A+, A-, B+, B-, O+, O-, AB+, AB-. Type O- is the universal donor, and AB+ is the universal recipient. Knowing your blood type is critical for emergencies, pregnancy (Rh compatibility), and donation. Learn your compatibility with our blood type calculator.

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Body Surface Area & BAC

Body Surface Area (BSA) is essential in clinical medicine for drug dosing accuracy. BAC (Blood Alcohol Content) measures alcohol in your bloodstream — affected by weight, gender, drinks consumed, and time elapsed. Never drive with a BAC above 0.08% (US legal limit). Use our BAC calculator and BSA calculator.

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Related Tools & Calculators

4 free tools linked to this guide

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Blood Pressure Calculator

Interpret blood pressure readings and track trends.

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Blood Type Calculator

Check blood type compatibility for transfusions.

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BAC Calculator

Estimate blood alcohol content based on drinks.

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Body Surface Area Calculator

Calculate BSA for clinical and fitness purposes.

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Frequently Asked Questions

What is a normal blood pressure reading?

Normal blood pressure is below 120/80 mmHg. Elevated is 120-129/<80. Hypertension Stage 1: 130-139/80-89. Stage 2: 140+/90+. Hypertensive Crisis: 180+/120+ (seek emergency care). The AHA recommends checking BP at least annually.

What blood type can I receive?

O- can receive only O-. O+ can receive O+/O-. A+ can receive A+, A-, O+, O-. AB+ can receive all types (universal recipient). B- can receive B- and O-. Always verify with medical professionals before transfusion.

How is BAC calculated?

BAC = (Drinks × 14g alcohol per drink) / (Body weight in grams × r) – (0.015 × hours). Where r = 0.68 for men, 0.55 for women (Widmark factor). Our BAC calculator provides estimates — actual BAC varies by individual metabolism.

What is Body Surface Area used for?

BSA is used primarily in medicine for drug dosing (especially chemotherapy), burn assessment (% TBSA), and physiological measurements. The DuBois formula or Mosteller formula are most commonly used: BSA(m²) = √(height(cm) × weight(kg) / 3600).

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