Physical Activity and Impact on Health
I had the absolute pleasure of working on an obesity program with Dr. Yoni Freedhoff about 2 years ago. If you don’t follow him on Twitter, I would strongly encourage you to do so and to visit his website Weighty Matters. With that project, he really wanted to correct the myth that just more exercise would solve the obesity crisis that we see in most developed nations around the world.
Exercise is not the magic solution to weight loss and obesity management, but has such a positive benefit on overall health. I thought I would do a quick post on some of the health benefits of exercise.
Exercise and Obesity
A review of the impact of exercise on obesity, titled The Effects of Exercise and Physical Activity on Weight Loss and Maintenance was published in 2018. In this article, there are some great statistics that can be used to counsel patients.
Impact of aerobic physical activity on weight loss
- < 150 minutes per week – no weight loss or minimal weight loss
- 150-225 minutes per week – weight loss of 2 to 3 kg
- 225-420 minutes per week – weight loss of 5 to 7.5 kg
They state that clinically significantly weight loss is:
- Possible with high exercise volume with aerobic exercise training alone (weight loss 0 to 3%)
- Very unlikely with resistance training alone (weight loss 0 to 1 %)
- Possible with high exercise volume with aerobic and resistance exercise training (weight loss 0 to 3%)
- Possible with caloric restrictions combined with aerobic exercise training (weight loss 5 to 15%)
Although obtaining significant weight loss is readily achievable, 80% of individuals are not able to maintain the weight loss. Although the data does not strongly support physical activity for weight reduction, 200-300 minutes of physical activity per week (60 minutes of daily walking) may be effective in helping to maintain weight loss.
Exercise and Cardiovascular Risk
While the attainment of clinically significant weight loss is an important health metric, the cardiometabolic benefits accrued from weight loss are particularly important in the treatment of people with overweight and obesity. Even as little as 2-3% weight reduction ash been shown to have positive effects on cardiometabolic risk factors. What is important to let patients know:
- Even in the absence of weight loss, there is improvement in cardiometabolic health with being physically active
Exercise and Cancer Risk
The Amount and Intensity of Leisure-Time Physical Activity and Lower Cancer Risk review was recently published. They evaluated the impact of physical activity on Cancer risk with the recommended amounts of physical activity (2.5-5 hours per week of moderate-intensity activity).
If a person engages in the recommended activity levels they had a significantly lower risk of 7 of the 15 cancer types studied, including:
- Colon (8%-14% lower risk in men)
- Breast (6%-10% lower risk)
- Endometrial (10%-18% lower risk)
- Kidney (11%-17% lower risk)
- Myeloma (14%-19% lower risk)
- Liver (18%-27% lower risk)
- Non-Hodgkin lymphoma (11%-18% lower risk in women)
For breast, colon, endometrial, esophageal adenocarcinoma, and head and neck cancer, there was increased reduction in risk with higher levels of physical activity.
A key point:
- When they adjusted for body mass index (BMI), there was minimal impact on the lower risk (with the one exception of endometrial cancer).
Physical Activity and Depression
The Joint and dose‐dependent associations between aerobic and muscle‐strengthening activity with depression: A cross‐sectional study of 1.48 million adults between 2011 and 2017 was recently published. This study found that the lowest risk of depression occurred in the group:
- Combining sufficient moderate-to-vigorous-intensity physical activity (MVPA) and muscle strengthening activity (MSA) (MVPA ≧300 min/week and MSA ≥2 times/week; adjusted prevalence ratio range: 0.54–0.63).
All associations remained after stratification and/or adjustment for sociodemographic (age, sex, income, education), lifestyle characteristics (body mass index, self‐rated health, smoking, alcohol), comorbidities (e.g., arthritis, diabetes, hypertension), and year of survey.
What Does this Mean for Practice?
- We should be recommending physical activity to match current Canadian guidelines
- Physical activity may not reduce weight, but can help with weight maintenance
- Physical activity reduces cardiometabolic, cancer, and depression risk
- Many of these physical activity benefits are independent of weight reduction