Exercise that makes your heart race and your lungs breathe hard and deep is called cardiovascular – it strengthens the heart and improves stamina. In contrast, exercise that forces you to contract muscles repetitively is called resistance training, and it can build and strengthen your muscles.
When you perform cardiovascular exercise, such as jogging, swimming, cycling, or brisk walking, you train your cardiovascular system. Your heart rate climbs, beating faster in order to pump more blood around your body, especially to the chest muscles that influence the depth of your breaths. As your body’s demand for oxygen rises, your breathing rate and depth rises accordingly. Your blood is saturated with as much oxygen as possible to provide your body with the energy it needs.
Muscles within the neck, chest wall, abdomen, and back coordinate to expand and reduce the size of your ribcage, so that the volume of air your lungs inhale and exhale increases.
Your tidal volume is the volume of air that flows into your lungs during a relaxed breath. If you try to breathe all the air out of your lungs, some air remains as your residual volume, and cannot be breathed out. Your vital capacity, the deepest breath you can take when training, is the rest of your lung volume excluding the residual volume.
Weight training builds your muscles, but so does dancing, gymnastics, and yoga – they are all forms of resistance training. A repetition (rep) is one complete motion of exercise. A set is a group of consecutive reps that will contract a particular muscle, or multiple muscles, repeatedly. You can target muscles to grow by choosing to perform a selection of sets and reps over a period of time.
Muscle Growth Process
Exercise tears muscle fibres, which are then repaired by satellite cells. Although muscle fibres are single body cells, they have many nuclei, and they incorporate the satellite cells, along with the nuclei – growing as they do so. During a break from exercise, your muscle fibres shrink, but they retain the nuclei from the satellite cells and regain their size quickly after re-training.
“When you sleep, hormones that stimulate muscle growth are released”.
—RATES OF EXERCISE—
Exercise intensity can be expressed as the percentage of your maximum heart rate. When you go out for a jog, you are working your heart at about 50 per cent of its potential power. Athletes who have reached their peak fitness can work their heart at maximum strength – 100 per cent. A fitness instructor can give you a target heart rate to reach when training (which varies with age) while achieving your fitness goals.