A daring proposition to change older adults’ aerobic recommendations
Sparling and colleagues [1] proposed a change to the physical activity recommendations for older adults, or to be precise aerobic recommendations. The authors suggested shifting the focus from moderate-intensity to light-intensity activity in order to offset potential hazards from prolonged sitting. As a rationale, they state that the health benefits of physical activity are dose-related [2] and the fact that older adults may find the recommended 150 minutes of moderate-intensity to be unattainable.
The official public health recommendations for older adults already fully embrace the concept of dose-response, in stating that: “lower risk of CVD has been observed with just 45-75 minutes of walking” and that “when chronic conditions preclude activity at minimum recommended level of prevention, older adults should engage in physical activity according to their abilities and conditions”. [3]
We would like to emphasise that older adults face natural age-related declines across all body systems even without any underling morbidity [4]. The lack of research on the health benefits of increasing light-intensity activities is recognised. Hence, it does not appear logical to change the recommendations without sufficient supporting evidence that light intensity activities will influence age –related changes in body composition or aerobic capacity. At this stage of knowledge this may be analogous to prescribing a “placebo” rather than a proven “effective dose”. Moreover, age-related declines in muscle strength and balance are major causes of morbidity, mobility impairment and disability in old age and these are not addressed by reducing sitting time or increasing light-intensity activity. Unlike cardio -metabolic risk factors, these functional impairments have no pharmacological treatment, whereas evidence –based exercise is a specific antidote.
We don’t understand the logic of compromising the desired dose of activity just because it is hard to reach. A recent meta-analysis of physical activity interventions delivered to community-dwelling aging population highlighted that studies recommending moderate-intensity physical activity reported significantly larger effect sizes (D = .58 ± .17, k = 10) than interventions recommending low-intensity activity (D= .26 ± .14, k = 13) [5]. Hence the evidence that it is less achievable doesn’t apply to community physical activity interventions in older adults.
Further, we contend that prolonged sitting in older ages is different to prolonged sitting among younger adults. In an Australian population study we found that the only significant predictor for prolonged sitting in older adults (upper tertile) was the presence of disability [6]. As sitting research is at an early stage, it is plausible that the association between sitting and all-cause mortality in old age is mediated by low cardiorespiratory fitness (CRF), in the same manner that the association between physical activity and all-cause mortality disappeared when CRF was simultaneously included as independent predictor [7].The clinical implication of this is to increase CRF, which can be achieved through moderate-intensity physical activity, but has not been shown to result from reduced sitting behaviour or increased low-intensity physical activity.
Last, we agree that relying on self-report physical activity questionnaires is problematic. However, it is also of concern to use absolute cut points in accelerometer data to delineate moderate-intensity from light-intensity activity for this age group. For the average 80 years old woman an intensity of 3 METs in on the borderline between moderate and vigorous intensity relative to maximal cardiorespiratory capacity. Thus we would suggest use of age-calibrated cut points for older adults, Accelerometer counts of 1041 per minutes were equivalent to 3.7 METs in a calibration study of older adults [8] and it shifted the population mean to 42 minutes of moderate-intensity activity, much higher than the 10 minutes estimated if a cut-point of 2000 counts were used [9].
In summary, it is premature and potentially harmful to suggest that reductions in sitting behaviour and light intensity activity should be the primary physical activity targets for older adults. The evidence for such proposed changes for health-related outcomes most relevant to older adults is lacking at present. Yet, changes to public communications regarding physical activity recommendations can confuse the general community, disseminate dissenting messages in the media and disorient policymakers.
Reference
1. Sparling PB, Bethany JH, dunstan DW, et al. Recommendation for physical activity in older adults. BMJ 2015:350 doi: 10.1136/bmj.h100[published Online First: Epub Date]|.
2. Haskell WL. Health consequences of physical activity: understanding and challenges regarding dose-respons. Med Sci Sports Exerc 1994;26:649-60
3. Nelson ME, Rejeski WJ, Blair SN, et al. Physical activity and public health in older adults: recommendation from the American College of Sports Medicine and the American Heart Association Med Sci Sports Exerc 2007;39(8):1435-45
4. Fiatarone-Singh MA. Exercise comes of age: rationale and recommendations for a geriatric exercise prescription. J Gerontol 2002;57A(5):M262-M82
5. Conn V, Cooper HM, J.C. V. Interventions to increase physical activity among aging adults: a meta analysis Annals of Behavioural Medicine 2002;24(3):120-200
6. Espinel PT, Chau JY, Van der Ploeg HP, et al. Older adults' time in sedentary, light and moderate intensity activities and correlates: Application of Australian Time Use Survey. J Sci Med Sport 2014;14:S1440-2440 doi: doi: 10.1016/j.jsams[published Online First: Epub Date]|.
7. Lee DC, Sui X, Ortega FB, et al. Comparisons of leisure-time physical activity and cardiorespiratory fitness as predictors of all-cause mortality in men and women. Br J Sports Med 2011;45(504-510)
8. Copland JL, Dale EW. Accelerometer assessment of physical activity in active healthy older adults. J Aging Phys Act 2009;17:17-30
9. Evenson KR, Buchner DM, Morland KB. Objective measurement of physical activity and sedentary behavior among US adults aged 60 years or older. Prev Chronic Dis 2012;9(11):010109 doi: http://dx.doi.org/10.5888/pcd9.110109[published Online First: Epub Date]|.
Rapid Response:
A daring proposition to change older adults’ aerobic recommendations
Sparling and colleagues [1] proposed a change to the physical activity recommendations for older adults, or to be precise aerobic recommendations. The authors suggested shifting the focus from moderate-intensity to light-intensity activity in order to offset potential hazards from prolonged sitting. As a rationale, they state that the health benefits of physical activity are dose-related [2] and the fact that older adults may find the recommended 150 minutes of moderate-intensity to be unattainable.
The official public health recommendations for older adults already fully embrace the concept of dose-response, in stating that: “lower risk of CVD has been observed with just 45-75 minutes of walking” and that “when chronic conditions preclude activity at minimum recommended level of prevention, older adults should engage in physical activity according to their abilities and conditions”. [3]
We would like to emphasise that older adults face natural age-related declines across all body systems even without any underling morbidity [4]. The lack of research on the health benefits of increasing light-intensity activities is recognised. Hence, it does not appear logical to change the recommendations without sufficient supporting evidence that light intensity activities will influence age –related changes in body composition or aerobic capacity. At this stage of knowledge this may be analogous to prescribing a “placebo” rather than a proven “effective dose”. Moreover, age-related declines in muscle strength and balance are major causes of morbidity, mobility impairment and disability in old age and these are not addressed by reducing sitting time or increasing light-intensity activity. Unlike cardio -metabolic risk factors, these functional impairments have no pharmacological treatment, whereas evidence –based exercise is a specific antidote.
We don’t understand the logic of compromising the desired dose of activity just because it is hard to reach. A recent meta-analysis of physical activity interventions delivered to community-dwelling aging population highlighted that studies recommending moderate-intensity physical activity reported significantly larger effect sizes (D = .58 ± .17, k = 10) than interventions recommending low-intensity activity (D= .26 ± .14, k = 13) [5]. Hence the evidence that it is less achievable doesn’t apply to community physical activity interventions in older adults.
Further, we contend that prolonged sitting in older ages is different to prolonged sitting among younger adults. In an Australian population study we found that the only significant predictor for prolonged sitting in older adults (upper tertile) was the presence of disability [6]. As sitting research is at an early stage, it is plausible that the association between sitting and all-cause mortality in old age is mediated by low cardiorespiratory fitness (CRF), in the same manner that the association between physical activity and all-cause mortality disappeared when CRF was simultaneously included as independent predictor [7].The clinical implication of this is to increase CRF, which can be achieved through moderate-intensity physical activity, but has not been shown to result from reduced sitting behaviour or increased low-intensity physical activity.
Last, we agree that relying on self-report physical activity questionnaires is problematic. However, it is also of concern to use absolute cut points in accelerometer data to delineate moderate-intensity from light-intensity activity for this age group. For the average 80 years old woman an intensity of 3 METs in on the borderline between moderate and vigorous intensity relative to maximal cardiorespiratory capacity. Thus we would suggest use of age-calibrated cut points for older adults, Accelerometer counts of 1041 per minutes were equivalent to 3.7 METs in a calibration study of older adults [8] and it shifted the population mean to 42 minutes of moderate-intensity activity, much higher than the 10 minutes estimated if a cut-point of 2000 counts were used [9].
In summary, it is premature and potentially harmful to suggest that reductions in sitting behaviour and light intensity activity should be the primary physical activity targets for older adults. The evidence for such proposed changes for health-related outcomes most relevant to older adults is lacking at present. Yet, changes to public communications regarding physical activity recommendations can confuse the general community, disseminate dissenting messages in the media and disorient policymakers.
Reference
1. Sparling PB, Bethany JH, dunstan DW, et al. Recommendation for physical activity in older adults. BMJ 2015:350 doi: 10.1136/bmj.h100[published Online First: Epub Date]|.
2. Haskell WL. Health consequences of physical activity: understanding and challenges regarding dose-respons. Med Sci Sports Exerc 1994;26:649-60
3. Nelson ME, Rejeski WJ, Blair SN, et al. Physical activity and public health in older adults: recommendation from the American College of Sports Medicine and the American Heart Association Med Sci Sports Exerc 2007;39(8):1435-45
4. Fiatarone-Singh MA. Exercise comes of age: rationale and recommendations for a geriatric exercise prescription. J Gerontol 2002;57A(5):M262-M82
5. Conn V, Cooper HM, J.C. V. Interventions to increase physical activity among aging adults: a meta analysis Annals of Behavioural Medicine 2002;24(3):120-200
6. Espinel PT, Chau JY, Van der Ploeg HP, et al. Older adults' time in sedentary, light and moderate intensity activities and correlates: Application of Australian Time Use Survey. J Sci Med Sport 2014;14:S1440-2440 doi: doi: 10.1016/j.jsams[published Online First: Epub Date]|.
7. Lee DC, Sui X, Ortega FB, et al. Comparisons of leisure-time physical activity and cardiorespiratory fitness as predictors of all-cause mortality in men and women. Br J Sports Med 2011;45(504-510)
8. Copland JL, Dale EW. Accelerometer assessment of physical activity in active healthy older adults. J Aging Phys Act 2009;17:17-30
9. Evenson KR, Buchner DM, Morland KB. Objective measurement of physical activity and sedentary behavior among US adults aged 60 years or older. Prev Chronic Dis 2012;9(11):010109 doi: http://dx.doi.org/10.5888/pcd9.110109[published Online First: Epub Date]|.
Competing interests: No competing interests