Exercise for Older Patients With Chronic Disease
Robert J. Petrella, MD, PhD
THE PHYSICIAN AND SPORTSMEDICINE - VOL 27 - NO. 11 - OCTOBER 15, 1999
In Brief: Coronary artery disease, hypertension, congestive heart failure, type 2 diabetes mellitus, osteoarthritis, osteoporosis, and cognitive disorders become more prevalent as people age. Besides delaying the onset of many of these conditions, regular exercise may improve function and delay disability and morbidity in those who have them. Further, exercise may work synergistically with medication to combat the effects of some chronic diseases. Special adaptations for older patients include lower-intensity exercise (eg, fewer repetitions), low-impact exercise (cycling, exercise while sitting), and modified equipment (smaller weights, special shoes, loose clothing). Unresolved issues include development of optimal strategies for motivating older patients to begin and maintain exercise programs.
People older than 65 constitute one of the fastest-growing population segments (1), and they have the greatest proportion of chronic diseases, disability, and healthcare utilization (2,3), although much of this is preventable (2,4,5). About 88% of people older than 65 have at least one chronic health condition (figure 1: not shown), and in many cases the condition impairs function and well-being (3). Even though regular exercise has proven health and functional benefits, inactivity increases as patients age: Older adults remain the most sedentary of adults (5-8). Although persons with chronic conditions or disability constitute most of the assisted-living community population older than 65, relatively few rigorous studies have focused on such subgroups. Risk factors for chronic disease, including coronary artery disease, hypertension, and type 2 diabetes mellitus, respond to exercise interventions in younger populations and likely will do so in the elderly as well. Given the higher incidence of these conditions with aging, even greater outcomes may be expected.
Poor exercise adoption and compliance in the chronically ill elderly may stem from the perception that chronic disorders are a part of normal aging. It is commonly believed that the elderly cannot respond to lifestyle interventions and that aging and chronic disease are inevitable, even though both perceptions have been disproved (9). Accumulating evidence indicates that risk factors are potentially avoidable rather than inevitable ("normal") and can be modified through lifestyle interventions, including exercise (10). Moreover, patients who adopt interventions can increase active life expectancy, decrease disability, and reduce healthcare costs. Although many questions remain about implementation (11,12), strategies for lifestyle changes and exercise programs can mitigate the effects of chronic disease in older persons.
The Goal: Postponing Disability
Care of the elderly has focused on managing chronic disorders rather than on the promotion of healthy lifestyle and prevention of chronic diseases. The crucial assumption behind efforts to change this focus is that changes in lifestyle and medical care can prevent, postpone, or reverse age-related morbidity. Vita et al (10) studied cumulative disability as related to three modifiable risk factors (body mass index [BMI], smoking status, and level of physical activity) in 1,741 University of Pennsylvania alumni over a 32-year period. Those who had the lowest risk (combined BMI < 25, nonsmoker, and high physical activity) delayed onset of functional disability by approximately 5 years, while those at highest risk (BMI > 27, smokers, and no regular physical activity) had earlier onset of disability, higher cumulative disability, and increased mortality over the study period (figure 2: not shown).
These findings support Fries' hypothesis (12) that if the average age at the onset of disability and chronic disease can be delayed by lifestyle interventions, then the total amount of disability will decrease. Health-promotion interventions made late in life as a form of secondary prevention may be as efficient as the primary prevention strategies to improve health-related behavior earlier in life.
This article reviews chronic disease and aging and the impact of regular exercise on disease course and physical function in aging patients. Because the incidence of many chronic diseases increases as patients age (figure 1: not shown), exercise interventions for representative diseases are reviewed; these include cardiovascular disease (hypertension and congestive heart failure), metabolic disorders (type 2 diabetes mellitus and dyslipidemia), musculoskeletal disorders (osteoarthritis and osteoporosis), and cognitive decline (Alzheimer's disease and vascular dementias).
Exercise vs Cardiovascular Disease
Sedentary living is an independent risk factor for cardiovascular disease; it doubles the risk of cardiovascular disease compared with that of active patients. Sedentary life imparts a risk similar in magnitude to that of smoking 20 cigarettes a day, an elevated cholesterol level, or mild hypertension. Besides being a proven strategy to prevent and treat hypertension, regular exercise can help prevent other associated chronic diseases (eg, type 2 diabetes mellitus and coronary artery disease), complement other lifestyle changes (eg, weight loss, decreased alcohol and salt intake), and improve quality of life.
In the Honolulu Heart Program study (13), physical activity was associated with remaining free of more than eight major chronic diseases in more than 12 years of follow-up. Additional favorable effects on other risk factors may also occur. Regular physical activity reduces the risk of mortality in persons older than 60; inactivity is associated with a 30% to 40% increased risk of premature death (5). Effects of exercise do not change with age, nor do they differ by gender or race (14).
Williams (15) has suggested that as we grow older, we increase in weight (16), become glucose intolerant (17), and have increased coronary heart disease (18) and associated risk factors (hypertension and hyperlipidemia (18,19)). Clinical trials in younger and middle-aged men have shown a relationship between higher activity levels and (1) reductions in total cholesterol, blood pressure, low density lipoprotein (LDL) and triglycerides (20,21) and (2) increases in high-density lipoprotein (HDL) (21) and fitness (20-22). The effects in the elderly are less well documented (22-24). Some authors speculate that to have the same effect as in younger patients, more increased-duration training at a lower intensity is required (6).
Lifestyle changes such as increased activity and a low-fat diet reduce blood pressure and provide general health benefit. The Joint National Commission VI guidelines recommend that all patients should be strongly encouraged to make lifestyle changes to lower blood pressure and reduce overall risk of cardiovascular disease. Unless additional risk factors or end-organ damage is present, patients with mild or moderate hypertension may use lifestyle modifications alone for 1 year before failed control warrants drug therapy. Physicians should resist the "quick fix" of prescribing antihypertensive medications without first recommending proven antihypertensive lifestyle changes.
It is important to specify the type of exercise when prescribing activity for a hypertensive patient. Dynamic exercise (aerobic work such as walking or running) has been confirmed as a blood pressure-lowering strategy (26,27). In contrast, less evidence indicates the efficacy of static exercise (isometric contractions or weight lifting) in reducing blood pressure. Hypertensive patients who use this form of exercise should be monitored closely, and those with severe hypertension or poorly controlled blood pressure should avoid it.
Exercise recommendations. Mild-to-moderate dynamic exercise (eg, walking or cycling) for 30 minutes per day (accumulated in one or multiple segments), done 3 or more days per week, has more antihypertensive effect than more vigorous exercise (5,14,23,28,29). This level of activity is about the level recommended by Canada's Guide For Physical Activity (30) and the 1996 US Surgeon General's Report (4) for general health benefit and should be more easily promoted for most patients than vigorous exercise might be. This amount of exercise in elderly patients can produce a 5- to 10-mm Hg decrease in blood pressure in as few as 4 to 5 weeks (29). Such a regimen is beneficial, is not likely to overburden the patient, and can help prevent injury and poor compliance (31). Because the key to exercise benefits is long-term maintenance of activity, behavioral-change counseling is important for guiding implementation and maintenance for older patients.
To obtain optimal benefit, however, patients with mild-to-moderate hypertension should engage in 50 to 60 minutes of moderate dynamic exercise three to four times per week. The hypertensive patient's response to exercise varies with the level of blood pressure, medication, and age. Interestingly, improvement in VO2 max with exercise is not necessarily associated with a similar reduction in blood pressure (14).
Those currently taking antihypertensive drugs should use exercise as an adjunct therapy; it may reduce the need for some medications. When exercise is combined with other lifestyle and antihypertensive drug strategies, the effects are even greater (27) and allow reduction in both number and dose of medication (32).
High-intensity exercise is not needed to achieve significant blood-pressure reduction. Because the benefits of isometric or resistance exercise are not well documented and because it acutely increases both systolic and diastolic blood pressure, it should not be used as the sole therapy. In patients who have controlled mild-to-moderate hypertension, however, resistance exercise may be combined with aerobic exercise if the program is monitored and limited to low resistance and high repetitions. Patients who do strength training should be advised not to hold their breath while lifting, but rather to exhale while lifting and inhale while lowering the weight.
Cautions. Issues regarding altered thermal regulation should be considered for elderly patients who may exercise in the heat. In addition, patients should be made aware that antihypertensive drug predilection for central or peripheral activity may affect physiologic responses to their exercise program (eg, slower or faster heart rates). Certain medications, primarily beta-blockers, can lower heart rate, requiring increased stroke volume to accommodate increased work; however, even though the drugs may limit patients' endurance, those taking beta-blockers can still achieve a training response.
Exercise in cardiac rehabilitation was previously thought not to benefit those with significant left ventricular impairment. In fact, bed rest was promoted in patients with heart failure (33). Starting in the 1980s, however, aerobic and mild resistance exercise training was found to be helpful (34,35). Benefits included improved endurance, ventilatory reserve, leg blood flow, and symptoms (36-38). (See "Moderate Exercise Helps Heart-Failure Patients," page 15.)
Several questions remain unanswered: Can positive training effects be maintained over the long term? Is training feasible in community settings? Can training affect mortality and morbidity? Systematic studies of older heart failure patients have not been done. To date, only about 600 patients have taken part in randomized trials of exercise training in the setting of congestive heart failure (39); however, large trials are under way and should eventually provide additional data.
Exercise recommendations. These patients should use their symptoms to guide their exercise duration and intensity (eg, using dyspnea scales). One technique is to add breaks in the exercise bouts every 5 to 10 minutes; this may prevent low compliance, fatigue, risk of injury, and circulatory compromise.
In heart-failure patients, more emphasis has been on resistance training than for other cardiovascular diseases. Many have considered this type of exercise risky because of the abrupt increases in myocardial oxygen demand (lowered angina threshold) or elevations in systolic pressure (lowered stroke threshold). Resistance training recommendations have not been rigorously determined, but the consensus seems to be to begin with one to three sets (12 to 15 repetitions each) for large muscles (legs and trunk) before adding small muscle groups (arms), and to avoid Valsalva's maneuver with lifting. When 15 repetitions can be tolerated, resistance should be increased.
A new and evolving regimen for congestive-heart-failure patients is interval training: Patients alternate 30 seconds of maximal aerobic exercise (100% effort of conventional exercise test, eg, on the cycle ergometer) with 60 seconds of rest, 10 to 20 times. For beginning, sedentary patients, one can shorten the period of maximum effort if the 30 seconds is too difficult, but not the total load, as the stimulus for increasing type 2 fiber requires this load (36). Since this is relatively new for these patients, refinements are certain to appear.
Metabolic Diseases: Dyslipidemia and Diabetes
Studies of exercise effects on dyslipidemia are limited primarily to those who have the highest event rates (those from ages 40 to 55; end-of-study ages limited to approximately 65 or 70); no studies have involved adults older than 70 or focused on women. The evidence is strongest for improvement in HDL concentrations; however, studies in slightly younger patients (eg, 60-year-olds) cannot be extrapolated to those older than 70. Existing studies included manipulation of other metabolic risk factors (eg, combined effects on lipids, glucose handling, and body weight), making them less useful for discerning the effect on lipids alone (ie, making it difficult to identify physiologically specific determinants).
There is a strong association between aging and the development of glucose intolerance and type 2 diabetes mellitus (40), although there is evidence that this may be primarily related to increasing levels of inactivity (41). Exercise in patients with diabetes promotes cardiovascular fitness and increased insulin sensitivity (lowering of plasma glucose) (42) and may lower the dosage of oral hypoglycemic drugs required. Furthermore, lifestyle interventions including regular exercise may be effective in preventing the development of type 2 diabetes (43-45). Pan et al (45) randomized 530 patients who had impaired glucose tolerance to one of four therapy groups: diet, exercise, diet and exercise, or control (usual activity). During the study period (1986 to 1992), patients in the diet, diet and exercise, and exercise groups had an incidence of diabetes that was inversely proportional to the treatment; this also appeared to be dose-related.
Ligtenberg et al (46) studied 58 patients with type 2 diabetes mellitus randomized either to an aerobic exercise or control group. Patients in the exercise group were supervised for 12 weeks, then instructed to exercise unsupervised for 14 weeks. The exercise group had an increased VO2 max and reductions in triglycerides and total cholesterol only as long as they were supervised; no change in glycemic control was seen at the end of the study (26 weeks). This study suggests that patients with type 2 diabetes need instruction to ensure adherence and prevent relapse.
In a randomized, controlled study (47), overweight African-Americans with type 2 diabetes (age 55 to 79) were engaged in 12 weeks of either supervised exercise and reinforcement mailings, educational classes and mailings, or usual care (control). Patients were assessed before the study and at 6 months. The group that received exercise supervision and mailings lost more weight, lowered their blood pressure more, and had better glycemic control than the other groups. In a similar 12-week study, Raz et al (48) showed that older type 2 diabetes patients who engaged in aerobic exercise had lowered triglyceride and glycosylated hemoglobin levels as long as a year after the study.
Low-intensity training of prolonged duration, such as walking, appears to be more effective than high-intensity training of shorter duration for reducing weight and controlling glucose and serum lipid levels because more of the energy fueling the exercise effort is derived from fat (49). Lehmann et al (50) found that type 2 diabetes patients who engaged in low-to-moderate intensity (50% to 70% of VO2 max) aerobic exercise experienced a 20% decrease in serum triglycerides and increased their HDL levels compared with control patients after only 3 months. Honkola et al (51) observed that type 2 diabetes patients who did twice-weekly circuit training at moderate intensity for 5 months deceased their levels of total cholesterol, LDL, triglycerides, and glycosylated hemoglobin compared with controls. These effects were even greater with higher-intensity exercise.
In sum, these studies suggest that for most patients with dyslipidemia and/or type 2 diabetes, low levels of exercise produce physiologic benefits. Higher levels of activity produce even greater health benefits.
Exercise recommendations. Exercise is an effective adjunctive treatment for patients who have type 2 diabetes, especially for those who are older. Patients should be instructed on how to integrate diet and hydration management with workouts and glucose monitoring, use of proper footwear, and adequate warm-up and cool-down routines. Patients may want to consult a podiatrist or athletic trainer with expertise in footwear. Timing high-energy snacks with workouts and balanced fluids should facilitate a euglycemic exercise. (See "Exercise in Diabetes Management: Maximizing Benefits, Controlling Risks," April, page 63.)
Usually, no specific exercise modifications are required for type 2 diabetes patients unless they have complications. Those with occlusive vascular disease and sensory or advanced microvascular neuropathy should take special precautions (eg, use low-intensity, low-impact exercise, wear special shoes). Exercise regimens should be adjusted to mitigate altered autonomic function during postural changes (eg, avoiding rapid efforts, quick standing maneuvers), and exercise in extreme environmental conditions (heat and cold) should be strictly discouraged. No specific recommendations are needed for patients with lipid disorders.
Medication for diabetes and dyslipidemia may be reduced as the training effects become manifest, though no effects of these medications on the training response have been demonstrated. Some patients who have muscle pain as a statin side effect may find that exercise exacerbates it, especially with heavy workouts. Less-intense workouts can reduce muscle pain; if patients insist on more intense workouts, they may require a switch to another drug.
In older patients who have osteoarthritis, exercise can improve pain control, proprioception, strength, flexibility, and endurance—all of which will improve functional independence. Until recently, however, evidence regarding exercise therapy for osteoarthritis had been equivocal (52). Many retrospective studies alleged a possible negative relationship between sport participation and certain occupations and the development of osteoarthritis (53-55); however, poor study design restricts their general applicability. This perception may have limited the use of exercise for these patients, despite published guidelines, including those of the American College of Rheumatology, that endorse it (eg, for knee osteoarthritis) (56).
Two well-designed intervention studies (53,57) showed that regular physical activity in patients with osteoarthritis reduced disability; however, exercise adherence declined by half 18 months after the study (58). Among patients who have multiple chronic conditions, exercise program nonparticipation and dropout remain problems (59). But programs that are specifically designed for the needs of subgroups may effect long-term behavior change. Morey et al (60) showed that 47% of patients in a Veterans Administration outpatient cohort were able to complete 2 years of supervised, multicomponent physical activity specifically designed for them.
Other recent studies also support the use of exercise in the management of osteoarthritis, specifically of the knee. Exercise that strengthens the quadriceps muscle and has an aerobic training component has been shown to be effective in reducing pain and improving function in a small cohort study (61). A large, randomized, multicenter study by Ettinger et al (57) showed that older patients who engaged in resistance or aerobic exercise had better pain control and functional outcomes at 18 months than patients who only attended an educational program. However, patients continued to take various medications while in the study, and there was no attempt to control for the class of medication.
In another study involving 172 older patients with osteoarthritis of the knee, a colleague and I (62) observed that exercise lessened knee pain and improved activities of daily living. When oxaprozin was given with the exercise regimen, the effect was additive. Whether exercise reduces analgesic use has not been systematically evaluated, however. Despite these positive findings, no dose-response relationship has been established between aerobic or resistance exercise and osteoarthritis pain relief. In addition, issues of long-term adherence and efficacy for osteoarthritis are still unresolved. (For more information on this topic, see "'Heavy' Exercise Increases Osteoarthritis Risk in Elders," page 15.)
Exercise recommendations. Pain influences exercise in arthritic patients. In addition, joint instability due to the disease itself or to associated loss of protective muscle tone, strength, and proprioception (63,64) may increase the risk of injury or limit exercise intensity. Bracing, adequate stretching, and doing fewer repetitions but more sets of resistance work are options.
It is important to include both range-of-motion and strength exercises. Strength training should include isotonic resistance (ie, lifting weights) or isometric exercise (ie, muscle contraction without joint movement) (65). Non-weight-bearing exercise such as water aerobics, swimming, chair exercises, and cycling are good modes, but positions that will lead to joint deformity, such as tight grips, should be avoided. Forcing these movements in joints already deformed may increase instability and pain. One clue that activity has been too vigorous is joint pain that lasts for more than 2 hours after exercise; hence, patients must recognize their limits and refrain from exercise during flare-ups.
A colleague and I (62) designed a progressive resistance program that combines less stress on the joints (lessened joint loading) and range-of-motion exercises for home use by patients with knee osteoarthritis (see the Patient Adviser, "Exercises for Patients with Knee Osteoarthritis," page 109). A small ankle weight was used in both isokinetic and isometric exercises in the 8-week program. Repetitions and sets were increased gradually. The program produced significant improvement in pain and functional ability for those who continued to exercise.
According to the World Health Organization's definition (66), about 30% of postmenopausal women have osteoporosis. Cooper et al (67) estimated that 20% excess mortality is associated with hip fracture due to osteoporosis; the cumulative lifetime risk of hip fracture for a 50-year-old woman can be as high as 60% (68). The value of exercise for preventing postmenopausal bone loss is still controversial. In recent meta-analyses (69-71) of studies addressing this question, exercise (including walking, running, and aerobics) significantly reduced bone mineral loss in the lumbar spine (L-2 to L-4) but not in the forearm or femur.
A fracture rate that has doubled in an aging population during the last 30 years has resulted in increased healthcare costs and morbidity, but if regular exercise can reduce bone loss, it may also reduce morbidity. Joakimsen et al (72) reviewed the effect of exercise on fracture in four follow-up and 18 case-control studies and found that physical activity (primarily leisure-time activity rather than occupational) reduces the risk for future fracture by as much as 50%. Gregg et al (73) studied the relationship between physical activity level and fracture risk during 7.6 years of follow-up in 704 women older than 65. Very active subjects had 36% fewer hip fractures than those who were the least active. No difference was seen in the incidence of wrist or vertebral fractures among groups, however. The authors concluded that the benefit of higher levels of activity for hip fracture prevention likely had multiple causes (ie, muscle strength combined with the effect on bone mass). This would explain why even those with low levels of activity had fewer hip fractures than those who were inactive.
Minimizing falls. Another significant contributor to age-related morbidity is falling. Fear of falling leads to a vicious circle: isolation, further restriction of physical activity, and increased risk of falls and fracture. Gillespie et al (74) identified 18 randomized controlled trials and 1 meta-analysis of the effect of exercise on the incidence of falling. They determined there was insufficient evidence to conclude that exercise decreases falls, but they did find that targeting multiple risk factors (such as reducing environmental hazards and increasing strength) decreases the frequency of falls. Similarly, the FICSIT study (Frailty and Injuries: Cooperative Studies of Intervention Techniques) (75) showed that patients who exercised had a 10% lower risk of falling compared with controls; those who also engaged in balance training reduced their risk by 25%.
Combination therapies. Combining exercise with other interventions (eg, calcium supplementation) has also been reported to be beneficial. In a 2-year randomized controlled study of exercise and calcium supplementation in 169 postmenopausal women, Prince et al (76) found that patients who only exercised did not reduce femoral neck bone loss, but that those who took calcium supplements and exercised did stem bone loss.
The exercise stimuli that are most effective in preventing bone loss, falls, and fracture are not fully understood. Resistance exercise has a more profound site-specific effect than aerobic exercise (even swimming and biking) (77), but both forms provide a weight-bearing stimulus to bone and decrease the likelihood of fracture.
Exercise recommendations. Reducing bone loss requires weight-bearing activity, which will also improve muscle mass and strength. For prevention, moderate-intensity exercises such as low-impact aerobics and vigorous walking are suitable. Jumping or jarring movements should be avoided. In addition, some movements may place undue stress on a vulnerable joint or bone and should not be done at all; these include standing on one leg and excessive flexion and extension of the spine. All exercises should be limited to about eight repetitions.
Much evidence supports the notion that physical activity and psychological functioning are related (78). Although the age-related decline of central nervous system function had been accepted as irreversible and inevitable (79), studies have shown that improvements in cognition (including memory, attention, reaction time, and intelligence) do occur in older participants in aerobic fitness programs. The underlying rationale has been that age-related reductions in cardiovascular function lead to brain hypoxia and cognitive decline. Cross-sectional studies support this (80). In such studies, active older adults consistently have had faster reaction times and better short-term recall, reasoning, and fluid intelligence than their inactive counterparts (81,82).
Prospective training studies are equivocal, however. A meta-analysis (83) in which physical fitness increased showed modest or mixed improvements in neuropsychological function. Methodologic problems included variability in exercise tasks, and suggested that the length of the exercise program and participants' initial fitness may be crucial. Wide variations in participant age may have diluted the training effects in the older cognitively impaired subjects.
Hill et al (84) followed 87 sedentary older adults who were assigned to an endurance training group or a nonexercising control group for 12 months. In addition to improving their aerobic capacity, the endurance group avoided any decline in memory, while memory in the control group did decline. Williams and Lord (82) studied 187 older women randomized to either an exercise or control group for 12 months. Those in the exercise group improved reaction time, strength, memory span, and measures of well-being. Thus, it appears that aerobic exercise can improve cognition and that the "dose" required is similar to that needed for cardiovascular and metabolic disease management. It remains unclear if a dose-response relationship exists between exercise and improved cognition, although an association between cognitive benefits and fitness gains tends to support its existence.
Exercise recommendations. Safety is the primary issue in exercise programs for those who have cognitive deficits. Issues that should be addressed include injury prevention, the possibility that patients will not report symptoms, and the effects of centrally acting medications, such as those used in behavior modification, on cardiovascular responses, spatial orientation, and perception. Proper attire, optimal environmental conditions, and simple equipment are essential, as are activities that are familiar, repetitive, and supervised (a low patient-to-instructor ratio is important). I have found that the use of chair exercise and household items (eg, knotted towels used to aid movement) with lively, familiar music is effective in promoting patient participation and functional gains.
Toward the Optimal Program
No consensus has been reached regarding the optimal physical activity program to produce health and functional benefits among older patients, but it will likely involve combined endurance, strength, and flexibility and balance activities. Measures to promote exercise adoption should be tailored to the patient's needs. For example, determinants of exercise maintenance in older patients with arthritis include initial fitness level, anxiety, social supports, and changes in pain. Physicians must be able to modify exercise interventions to make them suitable for patients with chronic disease and monitor progress using objective outcomes (eg, weight loss, heart rate, exercise time).
Successful aging is multidimensional, encompassing the avoidance of disease and disability, maintenance of high physical and cognitive function, and sustained engagement in social and productive activities (9). Aging is accompanied by an increasing amount of disability and functional impairment. Physical exercise may be the vehicle to confirm Fries' hypothesis (12), which states that if the average age at onset of disability can be delayed, then the total amount of disability will decrease. The initiation and maintenance of regular exercise of light-to-moderate intensity may reduce the morbidity associated with chronic disease in the elderly. Certainly, professional and public education efforts to this end are complementary and should gain a higher profile.
Dr Petrella is associate professor of family medicine and kinesiology at the University of Western Ontario and medical director of the Centre for Activity and Ageing at the Lawson Research Institute, St Joseph's Health Centre, London, Ontario. Address correspondence to Robert J. Petrella, MD, PhD, Heart Health and Exercise Laboratory, The Centre for Activity and Ageing, St Joseph's Health Centre, 1490 Richmond St N, London, Ontario, Canada N6G 2M3; e-mail to: [email protected].