JMIR Publications

ABSTRACT

Background:

Communicating physical activity information with sufficient details such as activity type, frequency, duration, and intensity is vital to accurately delineate the attributes of physical activity that brings positive health impact. Unlike frequency and duration, the intensity is a subjective concept that could be interpreted differently by people depending on demographics, health status, physical fitness, and exercise habits. However, activity intensity is often communicated using general degree modifiers, degree of physical exertion, and physical activity examples, which are the expressions that people may interpret differently. Lack of clarity in communicating the intensity level of physical activity is a potential barrier to an accurate assessment of exercise effect and effective imparting of exercise recommendations.

Objective:

This study assessed the variations in people’s perception and interpretation of commonly used intensity descriptions of physical activities and identified factors that may contribute to the variations.

Methods:

An online survey with a 25-item questionnaire was conducted using Amazon Mechanical Turk, targeting the adults residing in the US. The questionnaire included questions on participants’ demographics, exercise habits, overall health status, and perceived intensity of 10 physical activity examples. The survey responses were analyzed using R.

Results:

The analyses included 498 responses. The respondents included more females (55%) and Whites (80%). Numeric ratings of physical exertion after exercise were relatively well associated with the three general degree descriptors of exercise intensity such as light, moderate, and vigorous. However, there was no clear association between the intensity expressed with those degree descriptors and the degree of physical exertion the participants reported to have experienced after exercise. Intensity ratings of various physical activity examples significantly differed by the respondents' characteristics. On average, those who reported in poor health, not exercising regularly, or considered regular exercise was not that important for their health rated the intensity levels of the activity examples significantly higher than their counterparts (P <.001).

Conclusions:

This survey showed significant variations existing in how people perceive and interpret the intensity levels of physical activities described with general severity modifiers, degrees of physical exertion; and physical activity examples. Considering that these are among the most widely used methods of communicating physical activity intensity in current practice, a possible miscommunication in assessing and promoting physical activity seems to be a real concern. We need to adopt a method that represents activity intensity in a quantifiable manner to avoid unintended miscommunication.