| |
Physical Activity Guidelines
Updated
|
|
| |
All healthy adults ages 18 to 65 years need moderate-intensity aerobic
physical activity for at least 30 minutes on five days each week or vigorous-
intensity aerobic physical activity for at least 20 minutes on three days each
week, according to updated physical activity guidelines released by the
Association (AHA).
Further, adults will benefit from performing activities that maintain or increase
muscular strength and endurance for at least two days each week. It is
recommended that 8-10 exercises using the major muscle groups be
performed on two non-consecutive days. To maximize strength development,
a resistance (weight) should be used for 8-12 repetitions of each exercise
resulting in willful fatigue.
The preventive recommendation specifies how adults, by engaging in regular
physical activity, can promote and maintain health, and reduce risk of chronic
disease and premature death.
A companion recommendation is specifically applied to adults aged 65 and
older, and adults aged 50 to 64 with chronic conditions or physical functional
limitations
(e.g. arthritis) that affect movement ability or physical fitness.
The recommendations are an update and clarification of the 1995
recommendation from the Centers for Disease Control and Prevention
(CDC) and ACSM on the types and amounts of physical activity needed by
healthy adults to improve and maintain health. The intent is to provide a
more comprehensive and explicit public health recommendation for adults
based upon available evidence of the health benefits of physical activity.
The core recommendation remains fundamentally unchanged despite more
than 10 years passing since it was issued. New science has been
evaluated to understand the biological mechanisms by which physical activity
provides health benefits and the physical activity profile (type, intensity,
amount) that is associated with enhanced health and quality of life. This
publication reflects a review of that evidence, and considers key issues not
fully clarified in the original recommendation.
The updated recommendation for adults is improved in several ways.
1. Moderate-intensity physical activity has been clarified.
The 1995 document specified “most, preferably all days per week” as the
recommended frequency while the new recommendation identifies five days
per week as the recommended minimum.
2. Vigorous-intensity physical activity has been explicitly incorporated into
the recommendation.
To acknowledge both the preferences of some adults for vigorous-intensity
physical activity and the substantial science base related to participation in
such activity, the recommendation has been clarified to encourage
participation in either moderate- and/or vigorous-intensity physical activity.
Vigorous-intensity physical activity was implicit in the 1995 recommendation.
It is now explicitly an integral part of the physical activity recommendation.
3. Specified: Moderate- and vigorous-intensity activities are
complementary in producing health benefits, and a variety of activities can
be combined to meet the recommendation.
This combining of activities is based on the amount (intensity x duration) of
activity performed during the week and uses the concept of METs (metabolic
equivalents) to assign an intensity value to a specific activity.
4. Specified: Aerobic activity is needed in addition to routine activities of
daily life.
The updated recommendation now clearly states that the recommended
amount of aerobic activity (whether of moderate- or vigorous-intensity) is in
addition to routine, light-intensity activities of daily living, such as self care,
casual walking or grocery shopping, or that last less than 10 minutes, such
as walking to the parking lot or taking out the trash. Few activities in
contemporary life are conducted routinely at a moderate intensity and last for
at least 10 minutes. However, moderate- or vigorous-intensity activities
performed as a part of daily life (e.g., brisk walking to work, gardening with
shovel, carpentry) performed in bouts of 10 minutes or more can be counted
towards the recommendation. This concept was implied but not effectively
communicated in the original recommendation.
5.“More is better.”
The new recommendation emphasizes the important fact that physical
activity above the recommended minimum amount provides even greater
health benefits. The point of maximum benefit for most health benefits has
not been established but likely varies with genetic endowment, age, sex,
health status, body composition and other factors. Exceeding the minimum
recommendation further reduces the risk of inactivity-related chronic
disease. Although the dose-response relation was acknowledged in the
1995 recommendation, this fact is now explicit.
6. Short bouts of exercise are OK.
The original recommendation introduced the concept of accumulating short
bouts of physical activity toward the 30-minute goal, but there was confusion
about how short these episodes could be. For consistency, the minimum
length of these short bouts is clarified as being 10 minutes.
7. A muscle-strengthening recommendation is now included.
Muscle-strengthening activities have now been incorporated into the physical
activity recommendation. The 1995 recommendation mentioned the
importance of muscular strength and endurance but stopped short of making
specific declarations in this area. Available evidence now allows the
integration of muscle strengthening activities into the core recommendation.
8. Wording has been clarified.
Minor wording changes in the recommendation have been made to enhance
clarity in communications. For example, the term “aerobic,” or endurance,
has been added to clarify the type of physical activity being recommended
and to differentiate it from muscle-strengthening exercises, which are now
part of the core recommendation.
The updates also provide a clearer sketch of what combinations of
moderate- and vigorous-intensity activity can be performed to meet this
recommendation. Moderate-intensity aerobic activity is described as
generally equivalent to a brisk walk, or activity that noticeably accelerates the
heart rate.
The recommendations also summarize new research that links muscular
strength to health benefits, such as protection against bone loss and a
decreased risk of all-cause mortality.
The updated recommendations emphasize that relatively modest amounts of
physical activity will improve health; physical activity for cardiorespiratory
fitness and expanded health gains, such as weight loss, may require more
than a minimum 30 minutes of moderate activity most days of the week.
In general, there are more agreements than differences when it comes to
physical activity recommendations. Differences on “minutes-per-day”
recommendations appear because they are intended for different groups,
and may be gender-specific or relevant to overweight or obese individuals.
|
|
| |
|
