Calculate the body mass index of a patient weighing 164 pounds and who is 187 cm tall.
The Correct Answer and Explanation is:
To calculate the Body Mass Index (BMI) of a patient, we use the following formula: BMI=weight (kg)height (m)2\text{BMI} = \frac{\text{weight (kg)}}{\text{height (m)}^2}
Step 1: Convert weight from pounds to kilograms
164 pounds×0.453592=74.39 kg (approx.)164 \text{ pounds} \times 0.453592 = 74.39 \text{ kg (approx.)}
Step 2: Convert height from centimeters to meters
187 cm=1.87 m187 \text{ cm} = 1.87 \text{ m}
Step 3: Calculate BMI
BMI=74.391.872=74.393.4969≈21.28\text{BMI} = \frac{74.39}{1.87^2} = \frac{74.39}{3.4969} \approx 21.28
✅ Final Answer: BMI ≈ 21.3
Explanation
The Body Mass Index (BMI) is a simple, widely used tool to assess whether a person’s body weight is appropriate for their height. It provides a rough estimate of whether someone is underweight, normal weight, overweight, or obese. BMI does not measure body fat directly but correlates reasonably well with more direct measures of body fat in the general population.
In this case, the patient weighs 164 pounds, which is approximately 74.39 kilograms, and has a height of 187 centimeters, or 1.87 meters. Using the standard BMI formula (weight in kilograms divided by height in meters squared), we find: BMI=74.39(1.87)2=21.3BMI = \frac{74.39}{(1.87)^2} = 21.3
According to the World Health Organization (WHO) BMI classification:
- Underweight: BMI < 18.5
- Normal weight: BMI 18.5 – 24.9
- Overweight: BMI 25 – 29.9
- Obesity: BMI ≥ 30
A BMI of 21.3 falls within the normal weight range, suggesting that this individual’s weight is appropriate for their height.
However, it’s important to note that BMI does not differentiate between muscle and fat mass. For instance, a muscular athlete might have a high BMI despite having low body fat. Other assessments like waist circumference, body fat percentage, and fitness level provide a more complete picture of health.
In general practice, though, BMI remains a useful screening tool, especially when combined with other indicators, to assess risk for conditions like cardiovascular disease, type 2 diabetes, and hypertension.
