Step up the pace and intensity

Many exercise enthusiasts find it difficult to achieve results because their exercise lacks intensity. Exercise intensity determines physiological and metabolic changes in our body, but should not exceed safe limits. Checking your heart rate regularly during exercise is the easiest way to manage the intensity of the exercise routine.

Fitness benefits occur when you exercise harder than normal. You need to exercise at a level that increases your heart rate above normal, to improve your endurance and develop muscle strength. You must lift heavier weights than normal to develop strength. Similarly, you must stretch muscles beyond their normal lengths to improve your flexibility.

Exercise intensity is indicated by the amount of energy you expend, the amount of oxygen used, carbon dioxide produced or changes in heart rate. The higher the intensity, the shorter the session will be. You can improve lung and heart functions and overall fitness with lower intensity, longer duration of exercise or higher intensity and shorter duration. For most individuals, low to moderate intensity and longer duration are recommended. High-intensity exercise increases the risk of orthopaedic injury and is likely to discourage participation in the exercise programme.

Strength gains

To optimise strength gains, the intensity should be between 75 and 90 per cent of your maximum capability. At this intensity, most people are able to perform four to 10 repetitions. For strength training, the intensity usually ranges between one and six repetitions and in moderate intensity between eight and 12 repetitions. To develop muscular endurance, an intensity of 60 per cent of your maximum, or 15 to 20 repetitions, should be performed. Although low-to-moderate intensity is best suited for muscular endurance and toning, some strength gain will be experienced.

The exercise intensity should adequately stress your cardiovascular system without overtaxing it. The fitter you are, the higher your exercise intensity should be to produce further improvement in your fitness.

Dr Kenneth Gardner is an exercise physiologist at Holiday Hills Research Center; email: yourhealth@gleanerjm.com.