We are constantly told to exercise more. But how much exercise and how hard should we push our self in order to see some health benefits? This is one of the most common question I get from people I meet. There are plenty of confusion when it comes to exercise. We are reminded that more is better, yet, although death during exercise is rare, vigorous physical activity is associated with increased risk for fatality, particularly in individuals with high coronary risk. Our modern lifestyle also makes it harder to find time to hit the gym. Is 60 minutes, 3 times a week a good formula? What if we just don’t have enough time? Let’s find out more.
WHY WE SHOULD EXERCISE
Most of us already know that exercise is important. Studies have examined the role of physical activity in many groups—men and women, children, teens, adults, older adults, people with disabilities, and women during pregnancy and the postpartum period.
Exercise is known to provide the following benefits:
– Lower risk of heart disease, stroke, type 2 diabetes, high blood pressure, dementia and Alzheimer’s, several types of cancer, and some complications of pregnancy
– Better sleep, including improvements in insomnia and obstructive sleep apnea
– Improved cognition, including memory, attention and processing speed
– Less weight gain, obesity and related chronic health conditions
– Better bone health and balance, with less risk of injury from falls
– Fewer symptoms of depression and anxiety
– Better quality of life and sense of overall well-being
Research conducted by the U.S. Department of Health and Human Services, Office of Disease Prevention and Health Promotion concludes that the risk of dying prematurely declines as people become more physically active. Based on the chart, the relative risk reduce drastically when people performed 90 minutes of moderate- or vigorous-intensity physical activity. The risk continues to decline as people spend more time being physically active, but at a lesser gradient after the 180 minute mark. Based on the chart, we understand clearly that more is better, but it is not necessary to spend too much time to gain sufficient benefits from exercise. Hence, the Physical Activity Guidelines for Americans, 2nd edition, published by the U.S. Department of Health and Human Services, Office of Disease Prevention and Health Promotion recommends adults to get at least 150 minutes per week of moderate-intensity aerobic activity or 75 minutes per week of vigorous aerobic activity, or a combination of both, preferably spread throughout the week.
However, adults who are obese are recommended to achieve at least 300 minutes of moderate-intensity of physical activity a week or 150 minutes of vigorous physical activity a week; or an equivalent combination of moderate and vigorous exercise.
WHAT PHYSICAL ACTIVITY IS CONSIDERED TO BE MODERATE OR VIGOROUS?
Examples of moderate-intensity aerobic activities:
– brisk walking (at least 2.5 miles per hour)
– water aerobics
– dancing (ballroom or social)
– gardening
– tennis (doubles)
– biking slower than 10 miles per hour
Vigorous intensity activities will push your body a little further. They will require a higher amount of effort. You won’t be able to talk much without getting out of breath.
Examples of vigorous-intensity aerobic activities:
– hiking uphill or with a heavy backpack
– running
– swimming laps
– aerobic dancing
– heavy yardwork like continuous digging or hoeing
– tennis (singles)
– cycling 10 miles per hour or faster
– jumping rope
IS THERE A PRECISE WAY OF MEASURING INTENSITY?
Exercise is very relative. Some find it difficult to do 100 jump rope, whereas a fitter individual does 200 jumping rope as a warm up. There are ways to measure intensity more accurately. The most common way physical trainers measure intensity is by using METs, RPE or Targeted Heart Rate.
METs
MET stands for metabolic equivalent, which is one way that exercise physiologists estimate how many calories are burned during physical activity.
A good starting point to programming exercise and physical activity using METs is this brief table:
3.0 METs = Light intensity
3.0 – 6.0 METs = Moderate intensity
more than 6.0 METs = Vigorous
RPE
RPE stands for rated perceived exertion and is a scale used to measure the intensity of your exercise. I personally prefer to use the RPE method in my practice. The RPE scale runs from 0 – 10. The numbers below relate to phrases used to rate how easy or difficult you find an activity. For example, 0 (nothing at all) would be how you feel when sitting in a chair; 10 (very, very heavy) is how you feel at the end of an exercise stress test or after a very difficult activity. A ”talk test” is used to determine the level of intensity. A light intensity is when you’re able to talk comfortably. Moderate – able to talk but trying to catch your breathe occasionally. Heavy – some difficulty talking. Very heavy – unable to talk.
0 – Nothing at all
0.5 – Just noticeable
1 – Very light
2 – Light (can talk comfortably)
3 – Moderate (can talk but trying to catch your breathe occasionally)
4 – Somewhat heavy
5 – Heavy (difficulty talking)
6
7 – Very heavy (unable to talk)
8
9
10 – Very, very heavy
Moderate = Level 2-4
Vigorous = Level 5 onward
Watch this video to learn how to measure RPE
Targeted Heart Rate
This is also another personal favourite. Your target heart rate helps you determine your intensity accurately so you can get max benefit from every step, swing and lift. First, you need to determine your maximum heart rate by using this simple formula:
220 – (your age) = Maximum HR
Vigorous – 70-85% of your Maximum HR
In conclusion, to gain enough health benefits while reducing your risk of premature death, you should aim to achieve at least 150 minutes of moderate physical activity or 75 minutes of vigorous physical activity a week, along with strengthening and stretching exercises. I would personally recommend that you perform circuit weight training combined with your preferred cardio exercise for general well-being. Here’s an example of a weekly workout program for an average adult:
EXAMPLE A
Monday – Cardio (moderate) – 45 minutes
Tuesday – REST
Wednesday – Circuit weight training (moderate) – 30 minutes
Thursday – REST
Friday – Cardio (moderate) – 45 minutes
Saturday – REST
Sunday – Circuit weight training (moderate) – 30 minutes
TOTAL – 150 minutes of moderate physical activity a week
EXAMPLE B
Monday – Cardio (vigorous) – 20 minutes
Tuesday – REST
Wednesday – Circuit weight training (moderate) – 30 minutes
Thursday – REST
Friday – Cardio (vigorous) – 20 minutes
Saturday – REST
Sunday – Circuit weight training (moderate) – 30 minutes
TOTAL – 100 minutes of moderate-vigorous physical activity a week
EXAMPLE C
Monday – Cardio (vigorous) – 20 minutes
Tuesday – REST
Wednesday – Circuit weight training (vigorous) – 35 minutes
Thursday – REST
Friday – Cardio (vigorous) – 20 minutes
Saturday – REST
Sunday – REST
TOTAL – 75 minutes of vigorous physical activity a week
*NOTE: Before you begin to exercise, READ THIS FIRST! And consult your physician before beginning any exercise program.
SOURCES:
https://www.ncbi.nlm.nih.gov/pubmed/2073659
https://health.gov/paguidelines/ 2008/chapter2.aspx
https://www.heart.org/en/healthy-living/fitness/fitness-basics/aha-recs-for-physical-activity-in-adults
https://www.heart.org/en/healthy-living/fitness/fitness-basics/target-heart-rates
https://my.clevelandclinic.org/health/articles/17450-rated-perceived-exertion-rpe-scale
https://www.acefitness.org/education-and-resources/professional/expert-articles/6434/5-things-to-know-about-metabolic-equivalents