Which of the following tools can be used to assess physical activity levels?

Self-reported questionnaires are a well-established and widely used tool for assessing physical activity levels. These questionnaires allow individuals to provide information about their daily physical activity patterns, including frequency, duration, and intensity of different types of exercise. By gathering this subjective data, health professionals can gain insights into an individual's activity habits, which can be crucial for tailoring exercise prescriptions or interventions.

Using self-reported questionnaires can help capture a broad range of activities that might not be easily measured by other means, including leisure activities, household chores, and occupational activities. Additionally, these questionnaires can be administered quickly and can be cost-effective, making them accessible for both researchers and clinicians.

The other options do not primarily serve the purpose of assessing physical activity levels. Heart rate monitors provide data on physiological responses to exercise but do not directly measure the variety or extent of physical activity over time. Body mass index calculations are more focused on assessing weight relative to height and do not indicate specific activity levels. Blood pressure measurements offer insights into cardiovascular health but, similar to BMI, do not assess activity levels directly.