When I was preparing for my personal trainer certification nearly 3 years ago, I initially studied the ACSM’s Resources for the Personal Trainer. The first chapter portrayed a bleak health scenario in the American context. Increasing physical inactivity was linked to the widespread prevalence of non-communicable diseases and rising healthcare costs. Schools were also cutting back on physical education to focus on academia. The text made me feel like the personal trainer was in a unique position to influence public health and in some ways, even become the messiah of the unhealthy.
Kevin Carr’s Movement as Medicine presentation made me think of the personal trainer as being part of the first line of defence as the primary health care practitioner for most of an individual’s health needs (within the PT’s scope of practice of course). Each client exposure was an opportunity to change the client’s functional life for the better. But what is health really? I liked Dan John’s simple definition of health – it is the optimal interplay of organs. And does being physically active automatically mean that you are healthy? But first, what does it mean to be physically active?
From a health standpoint, I wondered what the minimum amount of exercise was that one had to do in order to stay healthy. Thought it might be useful information for those who despise any kind of physical activity. The ones who think the body is separate and inferior to the mind. You know, the extreme mind-over-matter types. And given the continuing lockdown situation, we are all the more prone to physical inactivity.
Arguably two of the most popular authorities on health-related information, the WHO and CDC, recommend that all active healthy adults (with certain exceptions) in the age group 18-64 should do the following:
So what is clear is that at least 150 minutes of moderate aerobic physical activity (or 75 minutes of vigorous activity or an equivalent combination) AND 2 or more days of muscle strengthening activities involving all major muscle groups is the bare minimum from a health standpoint for adults in the age group 18-64.
Physical inactivity is the fourth leading risk factor for global mortality (4-6% of deaths globally). Not a big deal? Consider this – it is a modifiable risk factor for over 25 chronic medical conditions (including type II diabetes, coronary heart disease, stroke, certain kinds of cancer, obesity etc) and premature mortality. By being physically active as per the recommendations, we can enjoy chronic disease risk reductions in the range of 20-30%. Now that is significant! Physical activity does not just prolong lifespan, it improves your quality of life by making you function better. How does being physically active actually help, what are the benefits? Check out this paper for the details. For the purposes of this post, I will limit myself to discussing physical inactivity and more specifically, aerobic physical inactivity for adults between the ages of 18-64.
This 2008-2018 trend analysis on adults meeting the recommendations from the CDC indicates that less than 1 in 4 American adults actually meet both the aerobic and muscle strengthening guidelines. Just about 50% of American adults meet the aerobic guidelines. India-specific data? India’s National Health Portal page is but a mash of the CDC’s and WHO’s pages on physical activity (so much for originality) and does not provide any statistics. I did find some related research papers however which indicate lack of sufficient data and/or that significant number of adults and children in India are physically inactive. People are classified physically inactive if they don’t meet the recommended guidelines.
Should you worry if you got only 133 minutes of moderate activity this week? Or are these guidelines somewhat arbitrary? The evidence cited by WHO is listed in their Global Recommendations on Physical Activity for Health document. Interestingly, these 2010 recommendations cite multiple papers by Warburton et al. In this most recent 2017 systematic review of systematic reviews (evidence inception FTW) examining the relationship between physical activity and health status by Warburton et al, validity of international threshold-based messaging has been questioned:
(Left image represents what is implied by threshold messaging, right represents actual relationship shared between physical activity and health status)
“…This threshold and expert opinion-based messaging is consistently promoted in the face of current literature (and often overlooked previous findings) that demonstrates that a volume of physical activity of half (or even less) of the 150 min/week recommendation can lead to significant health benefits…”Warburton, D. E. R., & Bredin, S. S. D. (2017). Health benefits of physical activity. Current Opinion in Cardiology, 32(5), 541–556.
“…it would appear that current international physical activity guidelines provide a dosage of physical activity that is very close to the optimal level for health benefits. However, as discussed above there has been a consistent knowledge translation error wherein the general public is often given threshold centered messaging that indicates that health benefits can only be accrued by meeting these targets. Statements such as ‘you should aim for’ have been replaced with declarations such as ‘you need to do’, ‘you must,’ or ‘you must engage in at least’ despite irrefutable evidence that strongly supports the importance of simply becoming more physically active…”Warburton, D. E. R., & Bredin, S. S. D. (2017). Health benefits of physical activity. Current Opinion in Cardiology, 32(5), 541–556.
Ok, so they’re saying current physical activity guidelines are promoting optimal needs which could be more than the minimum. What’s all the fuss about? More physical activity is better anyway right?
“For many individuals reaching the goal of 150 min/week of MVPA may not be feasible [9,10] and ‘off-putting’ creating an unobtainable target for a significant proportion of society . Knox et al.  estimated that the 150 min/week MVPA threshold would translate into an increase in physical activity behavior of 100–400%… A key concern regarding this knowledge translation error is the fostering of an ‘all or none’ and/or ‘one size fits all approach’ to physical activity promotion…”Warburton, D. E. R., & Bredin, S. S. D. (2017). Health benefits of physical activity. Current Opinion in Cardiology, 32(5), 541–556.
Ok, so they’re saying since most of us aren’t meeting the guidelines, there could be a mental barrier towards simply becoming more physically active (which is the goal). It makes total sense. It’s like how a lot of us say that we will follow our special fat loss nutrition plan to a tee from Monday (which somehow never comes). We instead choose to binge eat over the weekend when in reality making a small sustainable positive change in our eating behaviours might be more practical for some of us. We aren’t chasing perfection. We are simply striving towards more healthy behaviours.
Alright, is there an upper limit on how much physical activity we should do then? When do we stop seeing health benefits?
There is an extreme upper limit beyond which more physical activity leads to harm but it isn’t predefined or clear and more research is warranted. Most of us never reach that level though. Factors such as sufficient recovery also play a significant role.
What if I am a health freak and already nailing the recommended guidelines? We cool bro?
It depends. Yes, being physically active is one component of being healthy. It however, is NOT the only component. Remember that physical inactivity is distinct from sedentary behaviours. One can be both highly physically active and still engage in high levels of sedentary behaviour which has its own risks. Physical activity alone, in exclusion, will not always make you healthier. Other non-modifiable factors such as age, genetics, sex, ethnicity, etc along with modifiable factors such as smoking, abdominal obesity, poor nutrition, excessive alcohol consumption, stress, etc all play a role too.
So what should the guidelines say then?
“…Recent advancements in the field suggest that knowledge translation resources and recommendations should focus on the key determinants of healthy lifestyle behaviors rather than simply health outcomes. Promoting the enjoyment gained and the need to address multiple lifestyle behaviors is a good first step toward promoting healthy living.”Warburton, D. E. R., & Bredin, S. S. D. (2017). Health benefits of physical activity. Current Opinion in Cardiology, 32(5), 541–556.
In my opinion, for health purposes, the primary goal should be to be as physically active as one can be keeping in mind enjoyment of the physical activity, medical conditions, our busy schedules, and other commitments. Ideally, we should strive to meet the recommended activity levels for optimal health benefits. However, knowing the curvilinear dose-response relationship between physical activity and health status, any increase in physical activity even short of the non-existent 150 min MVPA threshold would help us accrue health benefits (especially when we are inactive). An integrated approach including addressing key lifestyle behaviours is important. Increasing physical activity, in isolation, may not always be beneficial from a health standpoint.
As a personal trainer, my goal would be to keep someone as physically active as they enjoy while striving towards the recommended guidelines for optimal health benefits. By focussing equally on prevention and not just treatment, we can help drive down healthcare costs and maybe one day become the messiah of the unhealthy. Fit pros ought to be given some sort of a bat signal every time humanity messes up in the health department. WHO, you listenin’? Being classified ‘physically inactive’ does NOT necessarily mean you are ‘unhealthy’. Being more active than current low levels of physical activity (even under the arbitrary optimal threshold) in a sustainable manner can definitely set you on the path to a healthy life!