The next logical question is what kinds of activity are recommended? The
answer lies in a newly published article in Circulation
which is the Journal of the American Heart Association, entitled, “Physical
Activity and Public Health: Update Recommendation for Adults From the American
College of Sports Medicine and the American Heart Association.”(1)
For all healthy adults aged 18 to 65 years of age the recommendation is a
minimum of moderate intensity aerobic (endurance) physical activity for a
minimum of 30 minutes on five days each week or vigorous intensity aerobic
physical activity for a minimum of 20 minutes on three days each week. A common
way to estimate energy expenditure for a given activity and understand what is
meant by these intensity designations is to use the concept of METs or
metabolic equivalents. When someone is sitting quietly, they expend 1 MET. The
moderate intensity activities expend from 3.0 to 6.0 METs and the vigorous
activities exceed 6 METs. In terms of METs, the minimum goal is to expend 450
to 750 METs per week in moderate intensity activities, vigorous intensity
activities or a combination of the two. A person can meet the minimum by a
combination of moderate and vigorous intensity activity. Moderate intensity
activity is generally equal to a brisk walk and noticeably increases the
heart rate. Vigorous intensity aerobic activity causes rapid breathing and a
substantial increase in the heart rate. Jogging is one example of vigorous
intensity activity. The table below gives some examples of common activities
and classifies them in these categories.
|
MET Equivalents of Common Physical Activities From Ainsworth, et al. 2000 |
||
|
Light < 3.0 METS |
Moderate 3.0 – 6.0 METs |
Vigorous > 6.0 METs |
|
Walking |
Walking |
Walking, Jogging & Running |
| Walking slowly = 2.0 | Walking 3.0 mph = 3.3 | Walking at a very, very brisk pace (4.5 mph) = 6.3 |
| Walking at a very brisk pace (4.0 mph) = 5.0 | Walking/hiking at moderate pace and grade with no or light pack (<10 lb.) = 7.0 | |
| Hiking at steep grade & pack 10-42 lb = 7.5-9.0 | ||
| Jogging at 5 mph = 8.0 | ||
| Jogging at 6 mph = 10.0 | ||
| Running at 7 mph = 11.50 | ||
|
Household & Occupation |
Household & Occupation |
Household & Occupation |
| Sitting – using computer, work at desk using hand tools = 1.5 | Cleaning – heavy; washing windows, car, clean garage = 3.0 | Shoveling sand, coal, etc. – 7.0 |
| Standing performing light work such as making bed, washing dishes, ironing, preparing food or store clerk = 2.0-2.5 | Sweeping floors or carpet, vacuuming, mopping = 3.0-3.5 | Carrying heavy loads such as bricks = 7.5 |
| Carpentry – general = 3.6 | Heavy farming such as bailing hay = 8.0 | |
| Carrying & stacking wood = 5.5 | Shoveling, digging ditches = 8.5 | |
| Mowing lawn – walk power mower = 5.5 | ||
The recommendation also indicates that bouts of moderate intensity aerobic activity at least 10 minutes in duration can count towards the 30 minute recommendation. Furthermore, because of the dose response relation of physical activity and health, people who wish to further reduce their risks for chronic diseases may do so by exceeding the minimum recommendations for activity. From the standpoint of weight loss, 60-90 minutes of moderate intensity physical activity daily seems to be necessary to maintain a weight loss of 30-50 lbs. The recommendation also calls for every adult to perform activities that maintain muscular strength or endurance at least two non-consecutive days a week. That should include 8-10 exercises involving all major muscle groups. This exercise should include sufficient weights to cause muscle fatigue after 8-12 repetitions of each exercise.
In the next post I’ll talk about exercise and people over the age of 65 or with chronic conditions.
For Your Health – Dr. Bob
Footnotes: (1) W. L. Haskell, et al. Circulation. 2007;116:1080-1093; originally published online Aug. 1, 2007