Most general guides for remaining healthy, getting fit and using regular exercise as part of a weight loss programs specify exercise times but are vague the rate or intensity of the exercise.
Various American guidelines recommend that adults should do at least 150 minutes of moderate physical activity in bouts of 8 to 10 minutes each week. That is 15 session or 2 per day. Recent research has shown that high intensity exercise for shorter periods of time can be just as effective.
So what is meant by moderate, vigorous and high intensity training? Why does the rate matter?
Moderate to Vigorous Exercise has been defined as a minimum intensity threshold rate of about 2,000 step counts per minute measured using an accelerometer or a step counter device.
Steps can be counted using smartphones, watches and mobile device apps and simple step counters you can buy from sports stores.
There is growing evidence that exercising at rates below this threshold does not achieve most of the desired benefits for either getting fit or losing weight.
A stroll in the park may be good for your mental state and well being, but it does not get the heart rate and circulation working hard enough to be an effective workout.
This article discusses exercise rates and frequency need to get fit and lose weight.
Moderate to Vigorous Activities
High Intensity Activities
Recent research has confirmed that it is the intensity of the activity that matters more than duration.
If you walk a long way very slowly you may not achieve very much. Speed up a little and you get more benefits. The old notion was that provided you covered the miles it did not matter much whether you took one hour or five. This is true only to a very limited extent in terms of working the muscles, but working slowly has very few benefits for the cardiovascular system.
One recent study involved about 2000 men and 2000 women, aged between 18 and 64 years of age. Each of the participants were asked to wear an accelerometers that recorded their physical activity. The team then looked at correlations with health and demographic data.
The physical activity levels were grouped into four categories by exercise duration and intensity:
Long, Very Intense Bouts
► Duration of over 10 minutes,
► Rate more than 2,020 counts (or steps) per minute
Short, Very Intense Bouts
► Duration of less than 10 minutes,
► Rate more than 2,020 counts (or steps) per minute
Long, Moderate Intensity Bouts
► Duration of over 10 minutes,
► Rate 760 - 2,020 counts (or steps) per minute
Short Moderate Intensity Bouts
► Duration less than 10 minutes,
► Rate 760 - 2,020 counts (or steps) per minute
The researchers then examine the body mass index (BMI) of each group as a measure of weight to height status and risk of obesity.
The analysis showed that each extra minute of higher intensity exercise undertaken each day lowered the risks of becoming obese by:
► 5% for women
► 2% for men
In terms of BMI the results were similar for both men and women.
Each extra minute of higher intensity exercise undertaken each day lowered the BMI by 0.07.
This is equivalent to a reduction of 0.41 pounds for each minute of regular exercise.
The table below show energy expenditure using the unit MET. This is a simple relative measure. The metabolic rate of a relaxed seated person is one Met
. The actually metabolic rates varies from person to person and the intensity of the activity. The MET is related to the standard metabolic rate, that is without exercise.
Research Studies have shown that:
The benefits if exercise are related to how much exercise you do, and the rate at which the exercise is done.
See this reference for more details.
Typical metabolic rates for some common activities | MET |
---|---|
Reclining, Sleeping | 0.8 |
Siting down and relaxing | 1 |
Standing still, not moving | 1.2 |
Most Sedentary Activities (office work, moving around the house, general school and office work) | 1.2 |
Driving a car | 1.4 |
Semi-Vigorous professions | 1.5 |
Light activities when standing up (shopping, light industry, some factory jobs) | 1.6 |
General Teaching | 1.6 |
General Domestic work – house keeping, washing and light gardening | 1.7 |
Walking on flat ground at 2 km/h (1.2 mph) | 1.9 |
Standing, moderately intense activities (shop assistant, house work) | 2 |
Building industry - Brick laying, general laboring | 2.2 |
Hand washing dishes, standing | 2.5 |
Gardening and Work around the home - raking leaves on the lawn, weeding | 2.9 |
Moderate industrial work | 3 |
Walking on the flat, 5 km/h (3 mph) | 3.4 |
Forestry work cutting trees | 3.5 |
Volleyball, Cycling (15 km/h) (9 mph) | 4 |
Calisthenics, Aerobics | 4.5 |
Building industry – heavy laboring | 4.7 |
Golf and Softball | 5 |
Gymnastics | 5.5 |
Swimming, Aerobics, Dancing | 6 |
Ice skating at 18 km/h (11 mph), Bicycling 20 km/h (12.5 mph) | 6.2 |
Digging with a spade, heavy gardening | 6.5 |
Basketball, Tennis, General Skiing, hiking in hills, Vigorous Skating or roller blading | 7 |
Handball, Racquetball, Hockey, Soccer, Cross County Skiing, Most team sports | 8 |
Running 12 min/mile | 8.5 |
Running at 15 km/h (9 mph) | 9.5 |