Health Reference Charts

Evidence-based reference charts and data tables for heart rate variability, blood oxygen levels, resting heart rate, blood pressure, and other vital sign ranges.

Heart Rate Variability (HRV) Chart by Age

Heart rate variability (HRV) describes variation between consecutive heartbeats. Population studies show that HRV generally declines with age, but reference values depend strongly on recording duration, posture, ECG versus PPG, processing, and the sampled population. The broad bands below are an illustration assembled from heterogeneous studies, not validated diagnostic intervals.

HRV Chart for Females by Age

Sex-stratified studies find age-related HRV differences, but the direction and size depend on the metric and protocol. The broad bands below are illustrative values assembled from heterogeneous studies, not validated female-specific diagnostic intervals.

Pulse Oximeter Readings Chart

A pulse oximeter estimates peripheral oxygen saturation (SpO2). The FDA says most healthy people have readings of 95–100%, but a reading is an estimate with uncertainty and must be interpreted with symptoms, trends, altitude, baseline disease and device limitations. The bands below are a general context guide, not a treatment protocol.

Blood Oxygen Level Chart

SpO2 estimates arterial oxygen saturation but does not diagnose the cause of a low reading. The FDA advises interpreting readings with symptoms, trends, baseline disease, altitude and known accuracy limitations. These bands provide general context and are not a protocol for prescribing oxygen or deciding treatment.

Resting Heart Rate Chart by Age and Fitness Level

The American Heart Association gives 60–100 BPM as the normal resting range for most adults and notes that active people may be as low as 40 BPM. It does not publish the age-by-fitness categories below. Those bands are retained only as a popular illustrative comparison and must not be treated as AHA thresholds or clinical grades.

Normal SpO2 Levels by Age and Condition

The FDA reports that most healthy people have SpO2 readings of 95–100%, while altitude and heart or lung disease can produce lower baselines. Age alone does not establish a different universal normal range. Clinical oxygen targets are prescribed for a condition and setting; they should not be inferred from a general table.

HRV Chart for Males by Age

Population studies show age-related HRV patterns in men, but values depend strongly on protocol and population. The broad bands below are illustrative values assembled from heterogeneous studies, not validated male-specific diagnostic intervals.

Heart Rate Training Zones Chart

Heart rate training zones divide your exercise intensity into five distinct zones based on percentage of maximum heart rate (%MHR). Each zone elicits different physiological adaptations and energy system usage. Understanding your training zones enables targeted workouts for fat burning, aerobic endurance, lactate threshold, or peak performance improvement.

Dangerous Heart Rate Levels Chart

For most adults, the AHA describes 60–100 BPM as the normal resting range. A number alone cannot identify the rhythm or determine whether cardioversion, pacing or defibrillation is appropriate. Symptoms and signs of poor perfusion drive emergency response; the bands below provide context rather than treatment thresholds.

VO2 Max Chart by Age and Gender

VO2 max (maximal oxygen consumption) is the gold standard measure of cardiorespiratory fitness, expressed in mL/kg/min. It represents the maximum rate at which your body can use oxygen during intense exercise. Higher VO2 max values are strongly associated with reduced cardiovascular mortality and all-cause mortality. This chart classifies VO2 max by age, gender, and fitness level based on ACSM normative data.

Blood Pressure Ranges Chart

Blood pressure is recorded as two numbers: systolic (pressure during heartbeats) over diastolic (pressure between heartbeats), measured in millimeters of mercury (mmHg). The American Heart Association classifies blood pressure into five categories that guide treatment decisions. Hypertension is a leading risk factor for heart attack, stroke, kidney disease, and heart failure.

Normal Respiratory Rate by Age

Respiratory rate (breaths per minute) is a vital sign that reflects pulmonary function, metabolic status, and neurological control of breathing. Often called the 'neglected vital sign,' an abnormal respiratory rate is one of the earliest indicators of clinical deterioration. This chart provides age-specific normal ranges based on WHO and pediatric clinical guidelines.

What Is a Good HRV Score?

There is no universal 'good' HRV number. RMSSD varies with age, recording duration, posture, breathing, ECG versus PPG and device processing. The bands below are common consumer-facing illustrations, not validated health grades or diagnostic thresholds.

Normal Sleep Stages Distribution Chart

Sleep architecture varies with age, health, medication, prior sleep and the scoring method. The proportions below are broad adult illustrations from polysomnography literature, not diagnostic targets for an individual or a consumer wearable.

Perfusion Index Guide

Perfusion index (PI) is the ratio of the pulsatile to non-pulsatile optical signal at the sensor site. Published healthy samples have markedly different distributions, and reviews conclude that universal normal and critical values have not been established across devices and settings. The bands below are an illustration of relative signal strength, not diagnostic ranges.