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| Fitness advice for everybody |
21-Jan-2008 |
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Providing your patients with a personalised exercise prescription ensures they enjoy the benefits of a healthier lifestyle. By Dr Steve Boutcher (PhD)
THE evidence supporting the beneficial effects of regular exercise on physical and mental health continues to accumulate.
It is now clear that being physically active is one of the major behaviours for preventing chronic disease. However, while general guidelines for exercise prescription have been established, exercise programs need to be personalised to ensure patient participation and realistic goal-setting.
Afterall, for some, working out at a gym may be a viable option whereas for others it may not be attractive. Also, what might be an effective program for one health variable may be ineffective for another. For example, an exercise program designed for losing weight may not be optimal for enhancing quality of sleep.
Therefore, exercise prescription involves choosing the appropriate physical activity mode, duration, frequency and intensity.
Recently, the AmericanCollege of Sports Medicine and the American Heart Association have published national guidelines on physical activity and public health.
The nature of all exercise is determined by its duration and intensity. The type of energy used by a particular form of exercise reflects its major characteristic. Some exercises are slow, aerobic in nature (eg, walking) and primarily use oxygen as fuel, whereas others are fast, anaerobic in nature and require no or little oxygen (eg, short sprints).
Exercise tips for specific needs
Weight
loss
A recent meta-analysis has confirmed that exercise interventions result in a small reduction in weight (about 1.15kg). However, studies in this area typically have combined men and women, which deflates the overall amount of exercise-induced weight loss because women lose less weight compared with their male counterparts.
Also, research studies typically report the mean average weight loss after an exercise intervention. As every study has weight loss responders and non-responders, averaging across all subjects disguises the true effect of exercise on weight loss. Thus, some men and women will lose significant weight whereas others may lose no weight or even gain weight. The goal for future research should be to identify why some people lose significant weight after exercising whereas others do not.
Recent research has shown that exercise modality and time of day may be important characteristics of successful exercise-based weight-loss programs. For example, it has been shown that 20 minutes of LifeSprints was far more effective in reducing fat and fasting insulin levels of young women compared with 40 minutes of hard, steady-state aerobic exercise. It is thought that LifeSprint exercise reduces fat more effectively because it produces high levels of catecholamines that induce adipocyte cells to release fatty acids.
Research has also shown that exercising in the morning before breakfast results in more fat burning than exercising later in the day. It is important that people trying to lose weight do not eat anything containing sugar or protein before they exercise. Both nutrients raise blood insulin levels, which discourage fat usage during and after exercise.
Muscle strength
Both men and women can achieve muscle strength by employing resistance exercises that use heavy weights with few repetitions, but women are less likely than men to show much increase in muscle size.
Muscle toning
Less weight and higher repetitions (eg, 15 bicep curl lifts of a 2kg dumb bell) tones the exercising muscles. However, muscles will not look toned unless the adipose tissue surrounding them is reduced. This is best illustrated in the abdominal area where hundreds of sit-ups will significantly increase the strength of the abdominal muscles but will not change their appearance due to the existence of the fat under the skin.
Body shaping
When fat loss is experienced it typically occurs from all sites proportionally. Thus, fat spot reduction and body shaping through typical exercise regimens is unlikely. If there is a small amount of fat surrounding a muscle then visible changes in the exercised muscle can occur within weeks.
General exercise prescription for people free of disease
We can split people into three general categories.
Those that have little time
and no access to facilities
For these people the exercise prescription should be home- or office-based. Goals should be to increase physical movement whenever possible throughout the day. For example, get the person to buy a pedometer and assess how many steps they take in a day. For a sedentary person this will typically be between 2000 and 3000 steps. Challenge the person to increase their number of steps to 5000 and eventually to 10,000. They can achieve this by including more walking strategies into their day (eg, park their car further from their worksite, take the stairs rather than the lift, take mini walks throughout the day).
When at home a good workout can be achieved when watching TV. The patient can perform a brief bout of resistance exercise using a theraband while sitting in their chair.
Those who have some
time and limited access
to facilities
For this group home and work strategies can be utilised as described above. This could be complimented by walks or jogs in the home or work areas (three times a week).
Those that have lots of
time and good access to
facilities
The ideal weekly exercise prescription is a minimum of 30 minutes on five days a week or vigorous-intensity aerobic physical activity for a minimum of 20 minutes on three days a week. In addition, every adult should perform activities that maintain or increase muscular strength and endurance on a minimum of two days a week.
General exercise
prescription for
management of disease
Heart disease
Exercise is helpful for patients who have coronary heart disease. Trials have indicated that cardiac rehabilitation with an exercise focus significantly reduced hyperlipidaemia, high blood pressure and mortality.
The exercise prescriptions described previously should be personalised for each cardiac rehabilitation patient. Thus, functional status, other diseases and medications, as with all types of patients, need to be considered.
Diabetes
Diabetes often accompanies obesity and a review of the literature has found that both aerobic and anaerobic exercise resulted in lower HbA1c levels. People who exercise regularly also have a significantly lower rate of type 2 diabetes compared with the inactive. Thus, regular physical activity, such as jogging and weight training, are important behaviours to prevent type 2 diabetes. The type of exercise prescription described previously has been shown to have positive health effects for patients with diabetes.
Weights and resistance exercise is also beneficial and has been shown to improve blood glucose control. However, the workouts have to be moderately hard and long (more than 45 minutes). There are also a number of considerations that need to be taken into account. Dangers include aggravation of metabolic disorders, exercise-induced hypoglycaemia and hyperglycaemia, foot problems (neuropathy), cardiovascular complications and musculoskeletal injuries.
Hypertension
Effective lowering of systolic and diastolic blood pressure can be obtained through participation in moderate-intensity exercise programs (such as walking or jogging) carried out three to five times a week. Regular aerobic exercise lowers blood pressure in about 75% of people with hypertension and an average of 11mmHg systolic and 8mmHg diastolic. Also, people with hypertension who exercise typically have an acute decrease in blood pressure for up to 10 hours after exercise, although this acute effect only happens after moderately vigorous aerobic exercise. Regular weight training and flexibility confer extra health benefits but do not appear to lower blood pressure.
Bone health
Both strength and balance training have been shown to prevent fractures and falls in older people. Research has shown that physical activities such as walking and swimming, do not generate enough bone stress to improve bone strength. Thus, weight training and resistance exercise appears to be the most effective exercise. Exercise may have an important indirect effect on osteoporosis by decreasing the chance of falling.
Pregnancy
The guidelines for pregnant women are similar to the recommendations described previously, but some important considerations must be taken into account. Pregnant women should not engage in highly vigorous exercise that significantly raises their core temperature. Exercise generally should get less vigorous across trimesters and should include mild warm-up and cool-down sessions. Extreme range of motion and ballistic stretching can be dangerous and are not recommended.
Mental health
A review of 30 studies of dementia patients found that participation in exercise resulted in increased cognitive function and fitness. Also, the incidence of dementia in physically active individuals is about half that of the sedentary. Exercise also appears to have a significant effect on depression. The effect has been estimated to be as effective as regular psychotherapy. More vigorous exercise seems to be the most effective, although modality does not seem to be that important. Studies have reported antidepressive effects after aerobic, anaerobic and resistance forms of exercise.
Older adults
The AmericanCollege of Sports Medicine and the American Heart Association have also recently produced exercise recommendations for older adults. These recommendations are similar to those described above with some important age-related considerations. These include the matching of exercise intensity to aerobic fitness levels, participation in activities that increase flexibility, and performing exercises to improve balance to reduce risk of falls.
With regard to the above, all patients need to have a personalised exercise program that takes into consideration absolute and relative contraindications for exercise. Thus, GP input into the design of the program is recommended.
TABLE 1 NATIONAL GUIDELINES ON PHYSICAL ACTIVITY
Component of exercise program:Frequency
Most effective general health outcomes:5 moderate aerobic sessions a week OR 3 moderate-vigorous aerobic sessions a week AND at least 2 muscular resistance sessions a week
Component of exercise program:Duration
Most effective general health outcomes:
at least a 30-minute session for moderate; at least one 20-minute session for vigorous/moderate
Component of exercise program:
Length
Most effective general health outcomes:
at least 26 weeks
Component of exercise program: Mode
Most effective general health outcomes:
Walking, jogging, resistance
Component of exercise program:Intensity
Most effective general health outcomes:Moderate and moderate-vigorous (starts to become difficult to talk)
TABLE
2.
EXERCISE CHARACTERISTICS
Aerobic
:Continuous moderate exercise that can last for more than 40 minutes. Fuel used is primarily oxidised fat and carbohydrate. Examples are walking, jogging, cycling, cross-country skiing and swimming.
Anaerobic
:Faster, more intense exercise that usually lasts no more than a minute. Fuel that supplies this form of exercise is mostly carbohydrate derived from glycolysis. Examples are basketball, a 400m run or any quick, short burst of walking, jogging, cycling or swimming.
Resistance
:Exercise that involves lifting weights or stretching a theraband. Endurance resistance exercise is performed using a high number of repetitions with a light weight. In contrast, strength exercises useheavier weights and fewer repetitions.
LifeSprints: Brief stop-start sprint exercise that uses multiple energy systems (anaerobic and aerobic). An example would be sprinting for eightseconds and then cycling slowly for 12 seconds on a stationary bicycle for 20 minutes three times a week.
EXERCISE PHYSIOLOGISTS
Exercise physiologists came under Medicare in 2006 and are trained to design exercise programs for chronic disease prevention and management. The majority of private health funds also offer a rebate. Exercise physiologists are university trained and required to be certified by the Australian Association of Exercise and Sport Science (www.aaess.com.au).
Most patients who work with exercise physiologists have medical conditions such as diabetes, cancer and heart disease. Exercise physiologists are trained in lifestyle-change techniques, which involve compliance strategies, exercise-based stress management skills and health behaviour changes. Consultation fees are usually about $45-$60, with the first five visits being covered by Medicare. Typically, their clients will be referred by a physician.
ADVANTAGES AND DISADVANTAGES OF DIFFERENT FORMS OF EXERCISE
Jogging
For time efficiency jogging is probably one of the best forms of exercise for health. For a typical male, jogging for 45 minutes burns up about 300Kcal (1236kJ) and exercising outdoors can provide a pleasant distraction. However, jogging is more stressful on the ankles, knees and hips compared with walking.
Aerobic dance
Aerobic dance gives muscles a workout but needs to be performed continuously to achieve a beneficial cardiopulmonary effect.
Resistance exercise
Resistance exercise helps retain muscle mass, which is easily lost when dieting and also decreases as people age. Resistance exercise can be carried out in a gym with weights or at home by stretching therabands.
Swimming
Compared with jogging, swimming is far less stressful on the joints and also involves more muscle groups. However, it is difficult to raise body temperature because the water effectively conducts away body heat. Being cold after swimming has been shown to increase appetite, which may be detrimental to weight loss.
Boxing
With the use of a punch bag, boxing provides both cardiovascular and anaerobic workouts.
Cycling
Cycling is an excellent form of exercise. However, exercise sessions typically have to be longer to burn up the same amount of energy used in a jogging session. But cycling is less demanding on joints. On the other hand, there is an increased risk of injury when cycling outside.
LifeSprints
The LifeSprint concept uses brief, high-intensity intermittent sprinting in a variety of exercise modalities (cycling, walking, swimming, rowing and resistance). Cycling LifeSprints have been shown to be effective at reducing body fat of young women. LifeSprints
References available on request.
Dr Boutcher (PhD) is an associate professor in the faculty of medicine at the
University
of
NSW
, where he directs the Fat Loss Laboratory.
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Posted by Sandy Loyall 5/05/2008 7:44:22 AM
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