Physical Indicators of Health & Interpreting Data
Why Physical Indicators Matter
Health professionals use physical indicators of health to move beyond what a person says they feel. While illness is a subjective experience, physical indicators provide objective, measurable data that can be compared against established normal values and tracked over time. The specification identifies five physical indicators that students must know: blood pressure, peak flow, body mass index (BMI), waist-to-hip ratio, and pulse rate (both resting and recovery after exercise).
Interpreting these indicators is not simply about checking whether a number falls within a range. It requires understanding patterns and trends in data, identifying increases, decreases, similarities and differences, and then considering the contributing factors that might explain those patterns. The four named contributing factors are: age, sex, lifestyle and environment.
Blood Pressure
Blood pressure is measured using a sphygmomanometer and expressed as two figures — systolic pressure (when the heart contracts) over diastolic pressure (when the heart rests between beats) — in millimetres of mercury (mmHg). The ideal reading for a healthy adult is around 120/80 mmHg. A reading of 140/90 mmHg or above is classified as hypertension (high blood pressure), which significantly raises the risk of heart disease, stroke and kidney damage. Readings consistently below 90/60 mmHg indicate hypotension (low blood pressure), which can cause dizziness and fainting.
Ideal adult blood pressure: 120/80 mmHg. Hypertension threshold: 140/90 mmHg or above. Hypertension is a major risk factor for heart disease and stroke. Many people have hypertension without experiencing any symptoms — this is why regular monitoring matters.
Peak Flow
Peak flow is measured using a peak flow meter and records the maximum speed at which a person can blow air out of their lungs, in litres per minute (L/min). It is particularly useful for monitoring conditions affecting the airways, such as asthma. Unlike blood pressure, there is no single universal “normal” range for peak flow — expected values vary significantly by age, height and sex. A healthy adult male of average height will have a higher expected peak flow than a child or an older adult. Practitioners always compare an individual’s reading against a personal best or predicted value based on their specific characteristics.
A reading significantly below the individual’s personal best or predicted value suggests that the airways are narrowed or inflamed. In an asthma patient, a peak flow that is 50% or below their usual reading signals a severe attack requiring immediate treatment. Trends over time — such as consistently falling peak flow in the morning — provide more useful clinical information than a single reading.
Body Mass Index (BMI)
Body mass index (BMI) is calculated by dividing a person’s weight in kilograms by the square of their height in metres: BMI = weight (kg) ÷ height (m)2. The NHS uses four categories to interpret BMI in adults: under 18.5 is underweight; 18.5 to 24.9 is healthy weight; 25 to 29.9 is overweight; 30 and above is obese.
The exam focuses on interpretation rather than just category identification. A student who reads a BMI of 32 and simply writes “obese” will not access the higher marks. Credit goes to linking the reading to contributing factors — for example: “A BMI of 32 places this individual in the obese category. Contributing factors may include lifestyle (a diet high in processed foods and low physical activity levels) and environment (limited access to green spaces for exercise in the local area).” This value → category → contributing factor chain is the expected analysis pattern.
NHS BMI categories for adults: underweight < 18.5; healthy weight 18.5–24.9; overweight 25–29.9; obese ≥30. BMI is calculated as weight (kg) divided by height in metres squared. Interpretation always considers contributing factors — age, sex, lifestyle and environment — not just the number itself.
A service user weighs 85 kg and is 1.70 m tall. To calculate BMI: 1.70 × 1.70 = 2.89 (height squared). 85 ÷ 2.89 = 29.4 (rounded to one decimal place). A BMI of 29.4 falls in the overweight category (25–29.9). To interpret this for the exam: lifestyle factors (e.g. low physical activity, high-calorie diet), environmental factors (e.g. working a sedentary desk job, living in an area with few leisure facilities), or age-related changes in metabolism could all contribute. Note that BMI does not distinguish between muscle mass and fat mass, so it may overestimate risk for individuals who are very muscular. A practitioner would not rely on BMI alone.
Waist-to-Hip Ratio
Waist-to-hip ratio is calculated by dividing the waist measurement (in cm) by the hip measurement (in cm). It indicates how fat is distributed across the body. Fat stored around the abdomen (“apple-shaped” distribution) carries a higher health risk than fat stored around the hips and thighs (“pear-shaped” distribution). The NHS uses sex-specific guidelines: for men, a ratio above 0.90 indicates increased risk; for women, above 0.85. Higher waist-to-hip ratios are associated with raised risk of cardiovascular disease, type 2 diabetes and metabolic syndrome.
Pulse Rate — Resting and Recovery
Pulse rate is measured in beats per minute (bpm). The normal resting pulse rate for an adult is 60 to 100 bpm. A resting rate below 60 bpm (bradycardia) may be normal in a highly trained athlete but in others could signal a cardiac problem. A rate persistently above 100 bpm at rest is tachycardia and may reflect stress, anaemia, infection, or cardiovascular disease.
Recovery rate — how quickly the pulse returns to its resting level after exercise — is a measure of cardiovascular fitness. A healthier heart and cardiovascular system recover more quickly. A slow recovery rate after moderate exercise suggests poor cardiovascular fitness and may indicate a need for lifestyle change or further investigation.
The four named contributing factors that affect all physical indicators are: age (blood pressure and BMI tend to increase with age; peak flow decreases in older adults), sex (men and women have different expected ranges for several indicators, including waist-to-hip ratio and peak flow), lifestyle (diet, exercise levels, smoking and alcohol consumption all influence readings), and environment (air quality, access to green spaces, housing conditions, and workplace hazards can all affect physical health indicators). When interpreting data in the exam, always consider which of these factors might explain a reading that falls outside the normal range, rather than simply labelling it as “unhealthy”.