Regular physical activity is undoubtedly an essential part of good health and should be practised by everyone. Regular physical activity will lower the risk of developing a number of chronic diseases including obesity, heart disease and cancer. For cancer survivors, the results of many studies suggest that exercise improves both their long-term prospects and their quality of life. Type 2 diabetics can improve their insulin sensitivity with exercise and diet, and can reduce their dependence on insulin.

For all of us, the benefits of regular exercise will be improved fitness and reduced fatigue. Exercise can also play a major role in relieving depression and anxiety. Many studies have shown that regular exercise can:

  • increase levels of HDL in our blood
  • lower high blood pressure
  • help improve body composition by burning fat
  • promote lower blood sugar levels
  • increase bone density
  • boost the immune system
  • improve mood and reduce depression.

How to assess fitness level and training requirements

Out of shape? Are you apple or pear shaped?

Abdominal obesity is now an acknowledged risk factor for diabetes, heart disease and certain forms of cancer. Dr Margaret Ashwell has developed a simple measure of height versus waist circumference that can be used to ascertain the health risk attached to your physique. This method is more accurate than the Body Mass Index (BMI) and has been validated by research from Cambridge University and the University of London (Have a go with the Ashwell shape chart below). Ideally, your waist measurement should be no more than half your height. Another valuable indicator of being overweight is the waist to hip ratio, which should be around 0.85 for women and 0.95 for men (i.e. a waist circumference smaller than hips in healthy!). If you are overweight then you should make a lifestyle change, and the healthiest is to combine exercise with a change of diet.


How fast can your heart go?

Calculation of your maximum heart rate is necessary before your exercise regime can be designed. This is a simplification but is very useful. It involves the simple sum of subtracting your age in years from the value 220. For example, if you are 60 years old, then 220 – 60 = 160. This is your maximum heart rate (MHR) and you should not over exert yourself to induce your heart rate to rise above 160 beats per minute.

Moderate intensity exercise 40-60% Max heart rate:

The moderate activity range is 40–60% MHR. The amount of activity which pushes your heart rate to 40-60% of the maximum will depend on your fitness. This can easily be calculated by taking your pulse rate at intervals during exercise (use your first two fingers to find the pulse on the side of your windpipe, count the pulse for 15 seconds and multiply by 4).

How to exercise following prolonged illness or inactivity:

Following illness or prolonged inactivity, you should start at the bottom of this range or lower and gradually work up to 60%. This is where joining a gym and gaining advice from health professionals is crucial. Another bonus is the presence of other like-minded individuals who can offer companionship, moral support and encouragement.

If you are ill or convalescing, there is a performance scale that you can use in agreement with your doctor. It is called the Karnofsky Scale and gives the following fitness ratings that can be used to design exercise programs (Table 1).

Table 1   Karnofsky Performance Scale
Fitness scale Indicators
100% No evidence of disease
90% Normal activity but minor signs of disease
80% Normal activity with effort and signs of disease
70% Unable to carry out normal activities but not requiring carers
60% Requires part-time carers
50% Frequent medical care and substantial assistance required
40% Disabled requiring full-time special care.
30% Severe disability with possible hospitalisation
20% Extremely ill requiring hospitalisation for treatment
10% Moribund

The 70–100% categories can be considered together and can start with 15 minutes of aerobic exercise per day to raise the heart beat to between 60–80% of the MHR. The 10 minute exercise time should be increased by 1–2 minutes per day until a maximum of 40 minutes per session is reached for at least five days per week. A reasonable time to reach the maximum would be about two months.

Those in the 50–70% categories must begin with a gentler regime of five minutes three times a day at 55% of their MHR, adding one minute per day upto a maximum of 10 minutes per session,  a total of 30 minutes per day. The sessions are then reduced to two per day and the times extended by a minute per day to a maximum of 15 minutes, again to a total of 30 minutes exercise per day. The final phase involves a reduction to one session per day, i.e. 15 minutes which is then gradually increased to a total of 40 minutes. The final stage will be the ability to maintain an exercise routine at 80% of the MHR for 40 minutes per day. This is a very sensible and safe way to gradually improve fitness. It can take more or less time depending on how rapidly your pulse rate returns to normal after each exercise session. If your pulse rate drops to normal in less than a minute after a workout, then you are ready to progress to the next stage. If not, then persevere at your current level until your recovery improves.

Some form of physical activity every day, consisting of least 30 minutes of moderate intensity aerobic endurance activity, will greatly benefit the health of older individuals [190]. Walk instead of driving short distances. Take the stairs instead of using the elevator or escalator. Other forms of exercise that many of us might not expect to have much health benefit include working on the car or cleaning the house. Participating regularly in some type of physical recreation is even better. Always remember that an active lifestyle is better than exercise in improving personal health and fitness. Instead of thinking in terms of a specific exercise program, work towards a permanently changed lifestyle to incorporate more activity. Do not forget that muscles used in any activity, any time of day, will contribute to fitness. Conversely, illness and associated bed rest lead to a rapid loss of muscle mass and cardiovascular fitness. It is crucial for convalescing patients to undertake supervised anaerobic resistance training to rebuild the wasted muscle, in addition to aerobic endurance exercise.

If you are seriously ill or incapacitated, you may lack the will to exercise, so a useful alternative to initiate muscle recovery could be the use of devices which use electrical stimuli to cause muscle contraction. There are a variety of inexpensive machines on the market which are sold mainly to health-conscious customers who wish to improve their figures and posture by muscle control. Many years ago during the Korean war, a study was carried out using these devices on US marines who were confined to foxholes with no room for normal exercise. At the end of the study after several days they were found to have increased their muscle strength by up to 40% without any traditional exercise. Normally this kind of inactivity would have led to muscle wasting and loss of strength.

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Site authors: Professor Rodney Bilton, Dr Larry Booth, and Joseph Bilton M.Sc B.Sc