Dr Sarita Bajaj,
Associate Prof Medicine,
MLN Medical College, Allahabad.
There seems to be widespread agreement from the time of plato to the present that diet and exercise rather than health care or doctors are the determinants of health.
To produce these effects exercise must be undertaken frequently, regularly and intensively. Long term adherence is also important.
There are two types of exercise - endurance training type and strength training type. Strength training exercises intended to strengthen select group of muscles such as weightlifting are usually not recommended for diabetics. Similarly exercises involving breath holding for long periods are not recommended as they increase blood pressure.
Endurance training exercises require greater use of energy and stimulate the heart and lung. The best exercise recommended is a stepwise increasing exercise plan or aerobic exercises. Plain brisk walking is the simplest and safest and can be started by anyone even past the middle age. Some exercises (jogging cycling, swimming) or strenuous sports may call for a medical check up.
The best exercise plan is one which is easy to implement on a regular basis.
The duration, intensity and frequency of exercise should be such as to produce a training effect and maintain it. For this purpose, it is important for the patient to understand maximum or target heart rate during exercise. The maximum heart rate (MHR) expected at a given age can be roughly derived by deducting a persons age from 220. The MHR also corresponds to maximum aerobic capacity or oxygen consumption. For routine purposes, measurement of oxygen consumption during execercise is not undertaken. Hence a patient can utilize the target or maximal heart rate in monitoring the intensity of his exercise.
A training effect is produced and maintained if exercises are undertaken to achieve 75% of the MHR, lasting 15 minutes every day and 5-6 days per week. The training effect is lost if the frequency of exercise is less than 3 times per week. In some patients 5% of the MHR cannot be achieved because of cardiovascular limitations. It is still worthwhile exercising these patients to achieve 40-45% of MHR, because this is also associated with increased glucose utilization.
The intensity of activity is decided by the heart rate (HR) response. The HR can be calculated by recording the beats at the wrist, neck or chest for ten seconds and multiplying by 6. A HR of 100-140 is desirable as a rough guide. Anything less than this or more than this will not yield desirable results. Other signs of stress include laboured breathing, light headedness or a pale face. This is the time to stop exercising.
Physicians are advised to routinely counsel sedentary patients to accumulate 30 minutes of moderate intensity activity equivalent to walking 3-4 mph for most healthy adults on most, preferably all, days of the week. The most sedentary patients should be encouraged to simply begin doing something and to make gradual changes over time. Doing something is better than doing nothing.
Perceived lack of time is the most commonly cited barrier to participation in regular physical activity. For many, finding a block of time to devote to exercise is difficult; however, exercise is effective whether it is completed in a single bout or split into briefer segments. For instance, 30 minutes of moderate-intensity activity per day could be accomplished by a single 30-minute walk or three 10-minute walks. Thirty minutes of activity could also be accumulated throughout the day by taking the stairs in lieu of the elevator, walking instead of driving short distances, using fewer labour saving devices, and doing housework or yardword. Many persons can readily insert shorter bouts of lifestyle activity into busy schedules. This point is worth emphasizing because the current low rate of participation in exercise may be due to the misperception that exercise must be uninterrupted in order to confer benefit.
An exercise or activity program should focus not only on decreasing current sedentary living habits but also on promoting long-term adherence.
A physician's active interest and encouragement helps the patient is succeeding in becoming more physically active and can be very helpful in increasing adherence. Long-term adherence is related to support from friends, exercise leaders, family, and especially spouses.
Exercise-related injuries are also likely to increase the risk for dropping out of vigorous exercise programs. Scientific evidence suggests that most exercise-related injuries are preventable.
Encouraging patients to make appointments to exercise (even with themselves) can be helpful. Exercising with others can also enhance committment because it is harder to "forget" exercise when someone else is involved.
Physicians who set a good example themselves further enhance the importance of the message they wish to send to patients.
Caloric Expenditure of Physical Exercise
|Walking (2.5 kmph)||210|
|Cycling (15 kmph)||400|
|Running (5 kmph)||600|
|Mopping floors, Gardening||300|
|Table tennis, Badminton||300|
(i) Exercising with excessively high blood glucose should be avoided, because the blood glucose may go even higher. If one finds that the blood glucose is too high just before exercise ie > 300 mg/dl (with type 1 diabetes), and > 400 mg/dl (with type 2 diabetes) - don't try to "work it off". Exercising will probably send it higher. Get back on the diabetes management plan.
(ii) Ketosis should be absent otherwise it gets aggravated.
(iii) Severe or progressive retinopathy should be ruled out.
(iv) Patients with advanced neuropathy should not carry out exercises involving lower limbs to prevent foot injury or pressure sores.
(v) Patients with unstable angina or poor left ventricular reserve should undergo cardiac evaluation before active exercise. Some of these patients may need to undergo exercise stress testing.
(vi) In the long term, exercising during an illness can delay your recovery or cause the illness to worsen. A chest cold, for instance can develop into bronchitis or pneumonia. It may take a few days, weeks, or months (depending on the length and nature of your illness) to get back to peak form, but try to be patient.
(vii) Exercising in extremely hot or cold conditions is dangerous for anyone. Your chances of experiencing hypoglycemia (low blood glucose) and dehydration increase in hot, humid weather, especially if you have an impaired thirst sensation, or you don't experience the usually symptoms of hypoglycemia. People with diabetes are also at an increased risk of frostbitten and cracked skin in extremely cold weather due to neuropathy (diabetic nerve diseae) and impaired circulation. When the weather is either very cold or very warm and humid, move your workout indoors.
(viii) Do not exercise for at least one hour after food and do not take food immediately after exercise. Exercise on an empty stomach before breakfast or dinner.
(ix) Any form of exercise should have a warm-up and cool down period of 5-10 minutes each. The former is necessary to avoid ischemic cardiac response and the latter to prevent (a) pooling of blood in the muscles, drop in cardiac output, postural hypotension and possible dizziness (b) Musculoskeletal problems.
(x) Do not take a cold bath immediately after exercise.
(xi) Avoid air conditioning during exercise.
(xii) Clothes that are worn during exercise should be porous.
(xiii) If one has spondylitis of neck or frozen shoulder, painful knee or backache avoid exercising the affected part unless advised by a doctor.
Hypoglycemia is the commonest risk associated with exercise. To avoid it certain precautions should be taken:
Hypoglycemia occurs due to speedy insulin absorption, increase in glucose disposal rate, depleted muscle glycogen stores, impairment in response of counter regulatory hormones (autonomic neuropathy, b-blockers) and/or interaction of hypoglycemic agents and exercise. Hypoglycemia is less likely to occur in type 2 diabetes and may not need any alteration in treatment programme but patients with type 1 diabetes will have to reduce insulin dosage by 10-20% or more.
Mathematics of weight gain and loss Slow creeping obesity:
A gain of 0.033 kg/day (33mg/day) = 1 kg a month = 12 kg/y = 60 kg in 5years
The weight conscious executive doesn't realize that the extra cup of tea he has everyday or a handful of chips adds to 1kg of weight in 2 months.
Tea/ a handful of chips = 150 calories = 8000 calories in 2 months 1 kg of fat = 7700 calories.
Walking is one of the best ways to enhance general health
1/2 hour of brisk walking = 200 calories burnt
1 lb(1/2 kg) of fat = 3500 calories
Therefore to burn 1lb of fat (1/2 kg) one needs to walk everyday for a minimum of 17 days to burn that amount with never a miss.
Maximal Exercise Heart Rate by Age
|Age||Predicted Maximal Heart rate||85% Max||75% Max||65% Max||60% Max|