As we age our hearts and arteries become stiffer. This cardiovascular stiffening plays a key role in hypertension, atrial fibrillation, and heart failure in older individuals (1).
Age-related cardiac stiffening is worse in those who are sedentary compared to those who exercise regularly (2).
Recent studies strongly suggest that regular exercise can prevent or minimize these age-related changes, thereby hopefully reducing the high rate of heart failure, hypertension and atrial fibrillation in the elderly.
In my post on fitness as a vital sign I briefly mentioned a fascinating study from 2014 which looked at 102 healthy seniors (age>64 years) and stratified them into 1 of 4 groups based on their lifelong histories of endurance exercise training.
Consider which of these 4 categories you fall into:
Sedentary subject-exercised no more than once per week during the prior 25 years.
Casual exercisers-engaged in 2-3 sessions per week
Committed exercisers-performed 4-5 sessions per week
Competitive “Masters level” athletes-trained 6-7 times per week
Exercise sessions were defined as periods of “dynamic activity lasting at least 30 minutes.”
The participants had sophisticated measures of their exercise capacity (max VO2), the size and mass of their left ventricles (cardiac MRI) and the stiffness of their left ventricles (invasive pressure/volume curves to calculate LV compliance and distensibility.)
This graph shows the key finding of the study: a markedly different pressure/volume curve in the sedentary and casual exercisers (blue and red dots) versus the committed or master exercisers. The two curves on the left correspond to a very stiff heart, similar to curves found in patients with heart failure.
The far right curve of competitive exercisers resembles that of a young heart.
The black triangle curve of the committed exerciser is in between these extremes
The study concludes:
“low doses of casual, lifelong exercise do not prevent the decreased compliance and distensibility observed with healthy, sedentary aging. In contrast, 4 to 5 exercise sessions/week throughout adulthood prevent most of these age-related changes”
It would appear we need at least 4-5 30 minute exercise session per week to forestall the age-related stiffening of the heart and lower our chances of getting heart failure, hypertension and atrial fibrillation.
Since this was an observational study there is always a chance that lack of exercise is not the causes of poor cardiac stiffness. It is conceivable that those of us with stiffer hearts tend to be more sedentary because of the poor cardiac function.
Can You Reverse The Age-Related Changes In Cardiac Stiffness?
If you have already reached middle age there is still hope for you as these same investigators recently published a study showing that cardiac stiffness can be improved with exercise. These findings imply that lack of exercise is the cause of worsening cardiac stiffness with aging.
This study identified 61 sedentary men in their mid-fifties and randomly assigned them to either 2 years of exercise training or attention control (a combination of yoga, balance, and strength training 3 times per week for 2 years) and measured their LV stiffness and max VO2 before and after intervention.
Max VO2 increased by 18% and LV stiffness declined from .072 to .051 in the exercise group but did not change in the control group.
The exercise training arm of this study involved a mixture of continuous moderate-intensity aerobic exercise combined with high intensity training. The high intensity portion of the program involved exercising at 90-95% of HR maximum for 4 minutes followed by a 3 minute active recovery period, repeated 4 times.
Over a period of 6 months under the guidance of exercise physiologists the participants had their exercise levels gradually increased. After 6 months they were training 5-6 hours per week, including 2 of the “high intensity interval” session and 1 long (>/= 1 hour) and one 30-minute base pace session each week.
By the sixth month, participants were training 5 to 6 hours per week, including 2 interval sessions, and 1 long (at least an hour) and one 30-minute base pace session each week.
How Much Exercise Do We Need To Minimize Cardiac Aging?
This chart from recent European guidelines on lifestyle for prevention of disease describes different intensities of aerobic exercise:
These guidelines suggest that if you engage in vigorous exercise such as running or jogging, cycling fast or singles tennis, you only need to achieve 75 minutes per week. Moderate exercise such as walking or elliptical work-outs requires at least 150 minutes/week.
Based on these recent studies on exercise and cardiac stiffness and the bulk of scientific literature on the overall health benefits of exercise I would advise for all individuals with or without heart disease
-If you are sedentary, become a committed exerciser.
-Committed exercise means some form of dynamic exercise 4-5 times per week
-If you are already a committed exerciser at moderate intensity levels consider adding to your routine one or two sessions of high intensity interval exercise.
-High intensity exercise will require you to get your heart rate up to 90-95% of your maximum
-Predicted maximal HR=220 -age. For a 60 year old this equals 160 BPM. 90% of 160 equals 144 BPM.