Merom and colleagues (1) reiterate well-established concerns about physical activity and health. We are, however, disappointed that in doing so they have misunderstood and distorted the intent and specifics of our commentary (2). This is especially surprising as we, along with reviewers and editors, were diligent to insure this would not be the case. Our concluding statement is clear: “We are not proposing that the 150 minute a week standard be abandoned. Rather, our purpose is to remind colleagues that a broad perspective to counseling is already embedded in the guidelines and that a whole day approach for older sedentary patients may help them move towards the recommended activity levels.”
Our focus is not on upending the mainstream approach, but rather to broaden it by advising patients to increase physical activity in a more graded manner. This approach is not unfounded or new; it is also proposed in the most recent consensus statements (3-5). To clarify further, our analysis focused on young-older adults (60-79), not old-older adults (> 80) or the frail elderly. While we agree that muscle strength and balance become increasingly important to health and function in aging adults, this topic was beyond the scope of our commentary. However, the potential effects or interactions of reducing sitting time and increasing light activity on these variables should not be discounted out of hand. Future biological and behavioral research may prove otherwise, but in the meantime such changes are unlikely to do harm. We agree with Merom and colleagues that, in general, research on the effects of replacing sedentary time with light activity is scare and we explicitly state that more is needed. This lack of evidence allows for different interpretations.
It is important to reiterate that in the large study of older adults in the UK (6), only 15% of the men and 10% of the women achieved the standard of > 150 minutes per week of moderate-intensity activity and this was based on an age-adjusted accelerometer cutpoint of >1040 cpm (7), not >1951 cpm. Moreover, an updated meta-analysis on interventions to increase physical activity among sedentary older adults (8) supersedes the 2002 paper cited by Merom et al. (9). The new analysis (from the same lab and including a decade of new studies) reported a small overall effect size (0.18) between treatment and control groups: a difference of 620 steps per day or 73 min of physical activity per week (intensity unknown). The treatment difference is small but clinically important, yet far short of the consensus target.
While we agree with many points raised by Merom and colleagues, their main concerns about our proposals are misguided. Our aim is to integrate more recent findings on the newly-identified hazards of too much sitting with the well-documented benefits of moderate-intensity physical activity, particularly as they pertain to advising older sedentary patients. The aim is synthesis, not division. We trust these clarifications along with a careful re-reading of our paper will show that our proposed approach is clear, safe and reasonable.
1. Merom D, Bauman A, Buchner DM, Fiatarone Singh M. A daring proposition to change older adults’ aerobic recommendations. BMJ 2015; rapid response 13 Feb 2015
2. Sparling PB, Howard BJ, Dunstan DW, Owen N. Recommendations for physical activity in older adults. BMJ 2015;350:h100
3. World Health Organization. Global recommendations on physical activity for health. WHO, 2010.
4. Department of Health. Start active, stay active: a report on physical activity from the four home countries chief medical officers. 2011.
5. Garber CE, Blissmer B, Deschenes MR, Franklin BA, Lamonte MJ, Lee IM, et al. American College of Sports Medicine position stand. Quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently healthy adults: guidance for prescribing exercise. Med Sci Sports Exerc 2011;43:1334-59.
6. Jefferis BJ, Sartini C, Lee IM, Choi M, Amuzu A, Gutierrez C, et al. Adherence to physical activity guidelines in older adults, using objectively measured physical activity in a population-based study. BMC Public Health 2014;14:382.
7. Copeland JL, Esliger DW. Accelerometer assessment of physical activity in active, healthy older adults. J Aging Phys Act 2009;17:17-30
8. Chase JA. Interventions to increase physical activity among older adults: a meta-analysis. Gerontologist 2014 Oct 7. pii: gnu090. [Epub ahead of print]
9. Conn VS, Valentine JC, Cooper HM. Interventions to increase physical activity among aging adults: a meta-analysis. Ann Behav Med 2002;24(3):190-200.
Competing interests: No competing interests