Exercise is so potent against lowering disease risk is due to many of the risk factors for cardiovascular disease (CVD) being strongly influenced by exercise. Blood pressure, diabetes, cholesterol, and lipids are influenced by exercise – and in quite a significant way. For example, when examining train conductors, a group of scientists discovered that those who were more active than their more sedentary counterparts had a 50% risk reduction in cardiovascular disease (1). That translates to an individual, whether 5,10, or 15 years down the road, being 50% less likely to die from heart disease!
As we age, our ability to pump blood throughout our body weakens with time—both the maximal capacity of the heart and the ability of our tissues to receive the blood declines. Physical activity is a great way to maintain a healthy heart and endothelial function. A resting heart pumps an average of 5 L of blood every minute – but during exercise, the heart can pump 10-15 L – up to 40 L per minute in trained athletes.
In addition to our cardiac output, the maximal capacity of our lungs is another important metric to keep an eye on as we age. VO2 max, just like physical activity, is a measure of fitness and is closely linked to all-cause mortality. Usually beginning in the fourth decade, VO2 max declines around 10% per year – this is mostly related to declining heart function and can manifest as fatigue or lowered fitness. Furthering the importance of healthy lung function, one study observed a 5-fold increase in mortality risk between the fittest 2.5% and the least fit 25% (for VO2 max) in the study population (2). Luckily, amongst the many things activity can improve, training can reduce the decline in lung function by ~50% (3).
What Type Of Exercise Regimen Is Optimal In Decreasing The Risk Of Heart Disease And It’s Risk Factors?
The number one type of exercise for reducing the risk of heart disease is aerobic exercise or “cardio.” This is due to the adaptations listed above, including improvement in maximal cardiac output, which results from an enlargement in cardiac dimension, improved contractility, and an increase in blood volume. Aerobic exercise modes include walking, running, biking, rowing, elliptical, skiing, etc. In an analysis of exercise type and intensity in relation to coronary heart disease (CHD) in men, Tanasescu et al. (4) found that men who ran for 1 hour or more per week saw a 42% reduction in CHD risk. Additionally, they found that a half-hour per day or more of brisk walking was associated with an 18% risk reduction.
Walking pace was found to be associated with reduced CHD risk independent of the number of walking hours. This finding, in addition to the significantly higher reduction in risk for men who run, indicates that intensity does matter. Research strongly supports the benefits of increased intensity exercise when it comes to physiological adaptations and reduction in risk of CVD and other chronic diseases (the more effort you put in, the more you get out of it).
Although when it comes to heart health, aerobic exercise is number one, this does not mean that the other half of the equation should be ignored! The other half of the equation being resistance training (or weight training).
Resistance training (RT) specifically leads to increased ventricular thickness and therefore increased contractile strength of the heart, so a favorable adaptation, but not as robust as the benefits in the heart that we get from intense aerobic exercise. In the same study as above, Tanasescu et al. (4) found that men who trained with weights for 30 minutes or more per week saw a 23% reduction in risk of CHD. Research shows that Adults who do not perform regular RT lose approximately 0.46 kg of muscle annually from the fifth decade onwards (5). Also, adults who do not perform RT experience a 50% reduction in type 2 muscle fibers, the fibers responsible for high levels of strength, by age 80 (5). The profound beneficial effects of RT on the musculoskeletal system can contribute to improved functionality and quality of life as well as reduced risk of musculoskeletal diseases and disability. Not to mention that having more skeletal muscle on our bodies helps improve many physiological factors that contribute to CVD risk, including glucose metabolism, our blood lipid profile, blood pressure, and basal metabolism.
Overall, a combined program of aerobic exercise with resistance training is recommended. Aerobic exercise is the best thing you can do specifically for cardiovascular disease risk, but don’t forget about all the benefits of resistance training- we should all be doing both!
If you are looking for help with goal setting, developing a sustainable fitness routine, or want to learn more about the benefits of exercise and how it can benefit your cardiovascular health, please reach out!
Clinical Exercise Physiologist