Physical Activity and Exercise Prescription
Physical fitness is a strong predictor of cardiac events. How fit we are is partly determined by our genetic make-up, but it is also important to remember that our fitness can be modified through structured activity, or exercise. Therefore, the terms ‘physical fitness’ and ‘exercise’ are closely linked.
Being ‘active’ does not necessarily result in improvements in physical fitness. To gain increases in physical fitness, you need to take part in structured activity that provides a physiological stimulus that is more than what the body is normally used to. This is known as ‘overload’. In cardiac rehabilitation, people with a higher cardiorespiratory fitness have significantly fewer cardiac events.
Cardiorespiratory fitness
Cardiorespiratory fitness is just one component of physical fitness; but it is a very important one. Like any component of physical fitness (such as strength, flexibility, co-ordination etc.) we can design what is called a ‘FITT’ principle to improve.
For example if the goal was to increase flexibility, we would select stretches and perform them: a certain number of times per week (Frequency); at a particular level of discomfort (Intensity); we would hold the stretch for an optimal duration (Time); and select the type of stretch that would produce the most effective change e.g. static stretch (where you hold the stretch without bouncing) versus ballistic stretch (where you include a bouncing action) (Type).
The current guidelines for cardiovascular exercise in the FITT principle format:
Frequency: At least 3 times per week
Intensity: Moderate
Exercising at 40 – 80% heart rate reserve maximum
Time: 20–30 minutes conditioning (plus warm-up and cool-down)
Type: Cardiovascular/Aerobic exercise
It is important to remember that structured exercise and physical activity together make up the 150 minutes advised in current guidelines. So, if a person participates in 3 times a week of the right intensity and type of activity for 30 minutes each time, this would result in 90 minutes of structured moderate intensity aerobic activity. They would still need to make up the remaining 60 minutes of moderate intensity physical activity over the week to achieve the 150-minute target.
It is important to remember that if your goal is to lose weight, you need to be partaking in the range of 250 – 300 minutes of moderate intensity physical activity a week (so roughly an hour a day)
Did you know? Every 1 MET gain is associated with an 8-17% reduction in all-cause mortality.
The benefits of aerobic (cardiovascular) exercise on the plaque formation process:
Cardiovascular exercise results in a shearing force on the endothelial wall of the artery. This force enhances the release of nitric oxide, improving vasodilation with improved blood flow through the coronary arteries.
The benefits of strength training:
As highlighted in the physical activity guidelines, strength training, performed twice a week, is also recommended. There are numerous positive effects associated with both aerobic endurance training and strength training on several health and fitness variables. One of the key benefits of strength training in the context of cardiac rehabilitation is the associated gains in lean body mass. Improvements in lean body mass raises our basal metabolic rate, meaning we can manage our weight much better. This is why it is important to incorporate strength training as part of the comprehensive programme for weight loss. Strength training also significantly improves our cardiovascular risk profile, by improving our insulin sensitivity, and also our glucose and lipid profiles.
Consequently, the key message is as much about reducing sitting time as getting people to achieve a minimum of 150 minutes of moderate intensity aerobic exercise. This mounting evidence does indeed highlight that in cardiovascular prevention and rehabilitation practice there is much to gain by simply encouraging people to stand and move around more frequently as part of their daily life. Moving away from sedentary behaviours and participating in even light intensity activity will greatly help improve health outcomes and decrease overall cardiovascular risk.
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Heart 2 Heart is a specialised physiotherapy service caring for clients post cardiac event and those at risk of a cardiac event. At the clinic we complete functional testing to test your capacity and establish your MET capability. We work with you to establish an exercise to optimise your performance and reduce your cardiac risk.
