Physical_Activity_Guidelines

Cardiac events, such as a heart attack or sudden death during physical activity, are rare. However, the risk
of such cardiac events does increase when a person suddenly becomes much more active than usual. The
greatest risk occurs when an adult who is usually inactive engages in vigorous-intensity activity (such as
shoveling heavy snow). People who are regularly physically active have the lowest risk of cardiac events both
while being active and overall.
The bottom line is that the health benefits of physical activity far outweigh the risks of adverse events for
almost everyone.
Risks of Sedentary Behavior
In general, sedentary behavior refers to any waking behavior
characterized by a low level of energy expenditure (less than
or equal to 1.5 METs) while sitting, reclining, or lying. The
Guidelines operationalizes the definition of sedentary behavior
to include self-reported sitting (leisure-time, occupational,
and total), television (TV) viewing or screen time, and low
levels of movement measured by devices that assess
movement or posture.
More time spent in sedentary behavior increases risk of:
• All-cause mortality;
• Cardiovascular disease mortality;
• Cardiovascular disease;
• Type 2 diabetes; and
Learn More
See Appendix 1. Physical Activity
Behavior: Intensity, Bouts, and Steps for
more information about METs.
Learn More
See Chapter 1. Introducing
the Physical Activity Guidelines
for Americans for a more detailed
discussion of the relationships of
sedentary behavior and health.
• Cancer of the colon, endometrium, and lung.
For inactive adults, replacing sedentary behavior with light-intensity physical activity is likely to produce some
health benefits. Among all adults, replacing sedentary behavior with moderate- or vigorous-intensity physical
activity may produce even greater benefits.
Chapter 2. Physical Activity and Health 45