The trouble with activity trackers … or not.

A recent study (1) found that a high level of cardiorespiratory fitness (CRF) was associated with an increased risk for localized prostate cancer.  The reasons for this are unknown.  The researchers speculate that perhaps this group was more likely to undergo preventative screening or detection.  However, higher CRF still showed a 32% decreased risk of cancer specific death for lung, colorectal, or prostate cancers; or 68% decreased risk of death from cardiovascular disease (CVD).  Note: some cancer treatments can be toxic to the heart.

From: Midlife Cardiorespiratory Fitness, Incident Cancer, and Survival After Cancer in Men:  The Cooper Center Longitudinal Study.

Lakoski, S.G., et al. JAMA Oncol. 2015;1(2):231-237

Figure Legend: Cardiorespiratory Fitness (CRF) and Risk of Incident Lung, Colorectal, and Prostate Cancer.  The low CRF group is the referent group relative to moderate and high fitness.  The error bars for moderate and high fitness represent the 95% confidence limits.  Adjusted for age, examination year, body mass index, smoking, total cholesterol level, systolic blood pressure, diabetes mellitus, and fasting glucose level.

The authors distinguish CRF from physical activity (I believe research data for both could be provided by valid and reliable activity trackers):

“Cardiorespiratory fitness is also highly reproducible and objectively assessed via incremental exercise tolerance testing compared with physical activity, which is largely determined by self-report questionnaires [and/or activity trackers?].  A prior study demonstrated that CRF is be a more potent marker of mortality than physical activity.  As such, given the current study findings and prior evidence, we contend that measurement of CRF should be used more frequently in the cancer prevention setting.”

I agree.  Furthermore, I would like to see physical activity, CRF, or aerobic capacity assessed when the cancer diagnosis process begins.  How beneficial would it be to tie fitness to an actual biopsy tissue specimen?  It’s interesting that CRF in the Cooper Clinic Longitudinal Study was assessed by the duration of performance achieved on a maximal treadmill test (2).  Then, based on subjects’ performance time, maximal oxygen uptake (VO2max) and maximal METs achieved were estimated, not measured.  If estimates can be used to assess CRF then it’s possible that some activity trackers could also be used.  Granted, screening patients before a CRF test is recommended, but some activity tracking data may already provide an adequate assessment of CRF.  A few devices already assess VO2max using heart rate, and with acceptable errors (for field measurements) in the 6-7% range (11, 12).  Stratifying data from activity trackers may be an important part of sorting its value: data for showing a training effect requires good accuracy; less accurate data is probably acceptable to assess CRF; and, data for tracking physical activity volume (MET-hours per week, etc.) can perhaps be the least precise of these – particularly since current population research using questionnaires tends to overestimate actual physical activity (13).

In discussing limitations of their study the authors mention something I believe may be significant for exercise-oncology research, and which I think validated activity trackers may be able to provide data for:

“CRF was assessed years prior to a diagnosis of lung, colorectal, or prostate cancer or death in men diagnosed as having cancer.  Thus, it is not known how changes in CRF and related behaviors, such as physical activity from the initial preventive health care to cancer diagnosis as well as changes in CRF and physical activity after diagnosis, may have had an impact on these current findings.”

I believe that exercise during the time from cancer diagnosis until first treatment will be found to have a positive impact on cancer treatments, treatment side effects, and on survival.  Sophisticated activity trackers that also estimate VO2max, or measure heart rate variability (HRV), which is related to CVD, have the potential to provide data in and around the diagnosis/treatment time period.  Furthermore, they can provide data across more cancer types by doing it in a more cost-effective manner than mailing out questionnaires or doing a CRF test on every cancer patient.  One overlooked benefit of activity trackers is that consumers subsidize the data.

Some useable physical activity data already exists in activity tracking databases but sits there underutilized.  Most physical activity data needs standard medical codes to improve its interoperability.  Other data could be retooled by correcting METs, which could provide more accurate estimates of energy expenditure (4, 5, 6, 7, 8), population specific intensity levels (9, 10), and might influence adherence to exercise training programs.  Regarding METs, an issue for some researchers is that the ‘standard’ MET (3.5 ml oxygen/kg/min) was based on the measurements derived from one 70 kilogram, 40-year-old man (5), and then applied to survey research.  Conversely, some activity trackers use ‘standard’ MET values from the Compendium of Physical Activities, which are intended for survey research, to estimate the energy expenditure and exercise intensity for an individual, which the Compendium advises is not its intended purpose.

Besides valid data, another issue activity trackers face is how should data be displayed or reported within an Electronic Health Record (EHR)?  Doctors are already over-worked and many complain about the burden of EHRs, adding physical activity data to their workload and expecting them to do something proactive with it (without reimbursement too) is not going to happen.  Make physical activity data easy for doctors to accommodate: summarize activity tracker data into an indicator of ‘compliance‘ or ‘non-compliance‘ with recommended physical activity guidelines, and provide that to an EHR.  For research, and for the more inquisitive and less time constrained physician, the underlying data supporting a compliance indicator could be accessible via EHR patient portals (e.g. EPIC’s MyChart).

Finally, a new study (3) found the ActiGraph GT3X+ accelerometer not to be very accurate at low and moderate intensity levels.  Of the few validation studies done on accelerometer based activity trackers, some were validated against the Actigraph as the criterion measure.  However, this study itself also missed an opportunity for better measurement when they estimated Resting Metabolic Rate (RMR) using the Schofield equations rather than measuring it with the Oxycon Mobile system they had – RMR is essentially what 1 MET is.  The study’s authors do disclose that they have receive funding support from Bodymedia, which Jawbone recently bought.

There is more to be sorted out in the consumer fitness/activity tracking eco-space.  I think devices and apps that produce valid and reliable data can make an impact in exercise-oncology research, particularly in the time periods surrounding diagnosis and treatment.

1. Lakoski, S.G., et al.  Midlife Cardiorespiratory Fitness, Incident Cancer, and Survival After Cancer in Men The Cooper Center Longitudinal Study.  JAMA Oncol. 2015;1(2):231-237. doi:10.1001/jamaoncol.2015.0226

2. Pollock ML, Bohannon RL, Cooper KH, et al.  A comparative analysis of four protocols for maximal treadmill stress testing. Am Heart J. 1976; 92(1):39-46.

3. Kim, Y., Welk G.J. Criterion Validity of Competing Accelerometry-based Activity Monitoring Devices. Med. Sci. Sports Exerc. 2015 Apr 23. [Epub ahead of print]

4. McMurray, R.G., et al.  Examining Variations of Resting Metabolic Rate of Adults: A Public Health Perspective. Med. Sci. Sports Exerc., Vol. 46, No. 7, pp. 1352–1358, 2014.

5. Byrne, N., et al. Metabolic equivalent: one size does not fit all. J Appl Physiol 99: 1112–1119, 2005.

6.  Kozey, S., et al.  Errors in MET Estimates of Physical Activities Using 3.5 ml·kg–1·min–1 as the Baseline Oxygen Consumption. Journal of Physical Activity and Health, 2010, 7, 508-516.

7. Wilms, B., et al.  Correction factors for the calculation of metabolic equivalents (MET) in overweight to extremely obese subjects.  International Journal of Obesity (2014) 38, 1383–1387.

8.  Hall, K., et al.  Activity-Related Energy Expenditure in Older Adults: A Call for More Research. Med Sci Sports Exerc 2014 Dec;46(12):2335-40.

9. Blair, C.K., et al.  Light-Intensity Activity Attenuates Functional Decline in Older Cancer Survivors. Med Sci Sports Exerc 2014 Jul;46(7):1375-83.

10. Herzig, K-H, et al.  Light physical activity determined by a motion sensor decreases insulin resistance, improves lipid homeostasis and reduces visceral fat in high-risk subjects: PreDiabEx study RCT..International Journal of Obesity (2014), 1–8

11. Montgomery, P.G., et al. VALIDATION OF HEART RATE MONITORBASED PREDICTIONS OF OXYGEN UPTAKE AND ENERGY EXPENDITURE. Journal of Strength and Conditioning Research 23(5)/1489–1495.

12. Lebouf, SF., et al. Earbud-based sensor for the assessment of energy expenditure, HR, and VO2max. Med Sci Sports Exerc 2014;46(5):1046-52.

13.  A systematic review of reliability and objective criterion-related validity of physical activity questionnaires. International Journal of Behavioral Nutrition and Physical Activity 2012, 9:103 pgs 1-55.

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A little exercise for me, a lot for you?

 

bikes,vintage  Cycling on twilight time

I often read stories about cancer patient’s (survivor, warrior, thriver, whatever we want to be called) physical accomplishments before, during, or after treatments – marathons, triathlons, ultras, century rides – all impressive stuff, even outside the realm of cancer.  The accomplishments seem understandable too, since exercise has been found to:

  • Improve survival in breast (1) and colorectal cancers by 50% (2).
    • Brisk walking of 2 1/2 hours per week produced the breast cancer results, but more vigorous exercise of 6 hours per week was needed for colon cancer;
  • Other researchers found moderate intensity physical activity to reduce risk of death from all causes by 60% among breast cancer patients (5);
  • and, cancer specific mortality from brain (4),andhigh grade, advanced, or fatal prostate cancers (3), were also reduced 43% and 70% respectively.
    • running 7.5 to 15.5 miles per week or walking briskly 12 to 23 miles per week for the brain cancer results, and 3 hours per week of vigorous exercise for prostate cancer.

Interestingly, more exercise did not reduce risk any further in the breast (1) or brain cancer studies.  However, for their results, the brain cancer subjects had to exceed the recommended physical activity levels (6) of 150 minutes of moderate intensity exercise per week.  Walking was also as good as running in the brain cancer study, subjects just had to walk farther.

What does this all mean for those of us affected by cancer?  Well, for the cancers mentioned above, if you’re not moving at the levels showing significance, perhaps it is time to get clearance from your physician, and start.  Practically, make exercise or physical activity a part of your weekly schedule.  It is easy to fill up your calendar with other things and people but forget to plan you into your week. Take a good look at your week, find days and times that work best to accomplish what you want, then write you into those time slots, and keep the appointment.  Book others to meet with you if needed, guilt can be the right motivator sometimes.

African American Family Parents and Children Cycling  Walking_2

Hypothetically, what if completing an Ironman Triathlon improved survival by 80%, would cancer patients, the majority of whom are sedentary, start training?  I wouldn’t be surprised if many did, determination can be great when faced with a cancer diagnosis.  However, even if willing to simply change their lifestyle, or intensely train for an Ironman, are we already hindering patients’ ability to do so by not pre-habilitating (8) them for the insult some treatments inflict on the body?  If most cancer patients do not already like to exercise, how are we ever going to convince them to start if we let their physical function decline further prior to or during the treatment process?

For those of us already in the exercise choir, and for cancer types other than those listed above, how much exercise is enough, and what may warrant caution (9) or be too much?  Unfortunately, most fitness stories remain just that, stories, unless we happen to be in a study, because, until physical activity is routinely recorded in oncology we will never know to what extent many physical accomplishments affect cancer survivorship (the ‘survivorship beginning at diagnosis’ definition).  Most of us in the cancer exercise choir, myself included, are just figuring it out as we go along, sometimes overdoing it (7), or maybe we’re not doing enough, and we share what we’ve learned with others.  Ironically, in spite of all the data we generate when training with our consumer fitness tools, there still isn’t the right statistical data to guide many of us.

senior man exercising in wellness club

Missing data …

A physical activity profile (using a short, scientifically validated, questionnaire) is not routinely recorded when extracting biopsy tissue from patients.  Is there evidence in tissue samples that could correlate physical activity to cancer treatment response rates and survival?  How are tissue samples different, if at all, between those who exercise versus those who don’t?  If different, can the differences be exploited to improve cancer treatment outcomes or to develop new drugs?  Exercise and physical activity are positively affecting survival for those cancers listed above, but how is this happening?  What are the physiological mechanisms, and are we overlooking routine biopsies as sources of evidence?  Exercise physiologists sometimes pay study volunteers and take muscle biopsy samples to find out what exercise did.  In oncology, other than pathology, how much thought is given to our biopsy samples, which patients pay for, and exorbitantly too?

I wouldn’t limit recording patients’ physical activity to biopsies only, we should be updating fitness profiles at diagnosis, first treatment, scans, and subsequent healthcare visits too.  The studies mentioned above were observational ones done over a number of years, some only assessing physical activity every two years (1,3), which doesn’t allow for teasing out information in the weeks specifically surrounding a cancer diagnosis or treatment.  Some physical activity questionnaires have gone electronic, but collecting data using paper forms, interviews, and calls to subjects is still done.  In today’s electronic world this sounds archaic, but this is how the best observational evidence has been obtained so far.Exercising on gym bikes.

Or … data to nowhere

With all the new consumer fitness products available we are still unable to get much of the data they generate into our electronic health records (EHRs).  My Garmin data, Moves data, and the information I type into my training and treatment log, all just sit there in electronic form somewhere in cyberspace.  My information cannot be pooled with the fitness data from others to search for statistical significance.  You can be sure the consumer fitness developers know a lot of things about me, but the products they have developed are generating data that goes nowhere – lots of data rather than ‘Big Data’ – my cancer and fitness story has no statistical power even though plenty of Information Technology (IT) is attached to it.

Recent announcements regarding consumer fitness and IT may change this and move us closer to continuously updated physical activity profiles by using data automatically uploaded through privacy ensured patient portals (EPIC’s ‘MyChart’ would be a good example).  Physical activity information could then be accessible when needed by clinicians from EHRs, and more importantly, tied to pathology, treatment, and other information within EHRs.  Apple’s collaboration with The Mayo Clinic, Nike, and the prominent EHR system, EPIC, appears to be headed in this direction.  However, without the broad use of internationally standardized exercise and physical activity codes for the common measures most exercise stakeholders are recording – steps, calories, heart rate, etc. – integrating the fitness data into EHRs will remain problematic.  Medicine wants valid standardized data and evidence before they will change clinical practice.  Our fitness stories, with isolated data on only one person, will not change clinical practice.

There is interest among cancer patients in allowing their data to be shared for research purposes, 87% reporting a willingness to do so (10) as long as privacy was adequately addressed.  How many of them have stories on the extreme ends of the physical activity spectrum and how is cancer survivorship going for them out there?  Fitness stories may motivate or guide others, but we also need statistical significance in order to impact clinical practice.

Swimming competition  Young Couple Jogging in Park

 

References:

1.  Holmes MD, et al., Physical activity and survival after breast cancer diagnosis. JAMA. 2005;393:2479-86.

2.  Meyerhardt JA, et al., Impact of physical activity on cancer recurrence and survival in patients with stage III colon cancer: findings from CALGB 89803.  J. Clin Oncol. 2006: 24:3535-41.

3.  Giovannucci EL, et al., A prospective study of physical activity and incident and fatal prostate cancer.  Arch. Intern. Med.  2005:165:1005-10.

4.  Williams PT, Reduced risk of brain cancer mortality from walking and running. Med. Sci. Sports Exerc. 2014 May;46(5):927-32.

5.  Irwin ML, et al., Influence of pre and postdiagnosis physical activity on mortality in breast cancer survivors: the health, eating, activity, and lifestyle study.  J. Clin. Oncol. 2008:26:3958-64.

6.  Schmitz K.H, et al., American College of Sports Medicine Roundtable on Exercise Guidelines for Cancer Survivors. Med Sci Sports Exerc. 2010 Jul;42(7):1409-26.

7.  Kano S, et al., [A case with myositis as a manifestation of chronic graft-vs-host-disease (GVHD) with severe muscle swelling developed after aggressive muscular exercise.] Rinsho Shinkeigaku. 2003 Mar;43(3):93-7.

8.  Julie K. Silver, MD and Jennifer Baima, M.D.  Cancer Prehabilitation: An opportunity to Decrease Treatment-Related Morbidity, Increase Cancer Treatment Options, and Improve Physical and Psychological Health Outcomes. Am J Phys Med Rehabil. 2013 Aug;92(8):715-27.

9.  Stan, D, et al., Pilates for Breast Cancer Survivors: Impact of Physical Parameters and Quality of Life After Mastectomy. Clinical Journal of Oncology Nursing. Volume 16, Number 2; pp:131-141.

10. Rechis, R, et al., The Promise of Electronic Health Information Exchange: A LIVESTONG Report.

 

Update:

The Future of Medicine Is in your Smartphone.  Eric J. Topol, MD.  The Wall Street Journal, 1/9/2015.

http://www.wsj.com/articles/the-future-of-medicine-is-in-your-smartphone-1420828632

Time to consider ditching the chemo recliner?

IMG_0224

A cancer study published earlier this year found some very interesting results regarding the blood flow of tumors at rest versus during exercise.  For some of you, it may be a surprise to learn that this had not yet been studied in animals or in humans.  For me, I have been waiting for something like this for the past 2 1/2 years, since I began looking into exercise and cancer survivor research.  In spite of all the cancer fundraising events where people exercise to raise money for cancer research, little is know about what all that exercise may be doing to tumors.

The study (only in rats) examined prostate tumor tissue at rest and during low to moderate intensity exercise.  At rest, the blood flow to prostate tumor tissue was less than that of the surrounding prostate tissue and less than that of the control animals’ prostate tissue.  However, during exercise, the prostate tumor tissue blood flow increased 200%, significantly above that of the surrounding prostate tissue or that of the control animals’ prostate tissue, both of which remained the same as at rest.

If you’ve ever had chemotherapy or accompanied someone who has, you may remember those nice, comfortable, recliners for resting in while the drugs pump into the veins.  Well, if we could extrapolate the results of this study, resting in recliners would seem to limit blood flow into tumors at the very time that we want it to be at its maximum – while the drugs are flowing in.  Now, before you get too concerned about infusion nurses yelling at chemotherapy patients to ‘push it’ for 30 more seconds on the treadmill, remember, the study used low to moderate intensity, and as I wrote previously, intensity is relative to each cancer patient’s fitness level.  For many patients, I would not be surprised if strolling around the infusion ward was low to moderate intensity exercise, and for some, maybe even near maximal intensity.  Currently, one of the best parts of chemo infusions could actually be the walking out of the infusion ward when it’s over, plus, any ‘exercise’ (shopping, walking, work/household duties) done afterwards until the chemotherapy drugs are metabolized or eliminated.

They let us walk into and out of the chemotherapy infusion wards, why not walk during infusion?  Some concerns may be over balance due to any sedatives administered as a part of the infusion process.  True, but some sedative doses can be decreased.  When I had to drive myself home after a series of infusions, they cut my Benadryl in half so that I wouldn’t be woozy for the drive home.  There must be other sedatives as well that could be similarly adjusted.

An editorial that accompanied the cancer study I cited above, mentioned how emerging evidence is ‘beginning to challenge the current perception of exercise as a “soft” intervention that “cannot hurt.” ‘  This is similar to what cardiology went through decades ago.  Then, patients were sent home to bed rest for weeks after a heart attack.  Once more research started coming in, showing that patients did better if they started exercising soon after their heart attack, cardiology started getting patients moving.  This may be where we are with cancer treatments and exercise – leaving the ‘soft’ intervention realm and moving into the “A Team’ of evidence that shows improvements in existing cancer treatments.   But we need human studies first, this is why I started WorkOut Cancer.

I hope you’ll help us to move evidence like this along into human studies.  This is not rocket science but basic physiology, much of which has been overlooked in favor of billion dollar drug development.  Fair enough, there are many effective cancer drugs, I’m not opposed to them, but can we improve the delivery of those drugs with something as simple as switching from recliners to strolling the infusion ward halls?  Furthermore, what else might we discover about these physiological mechanisms that might improve cancer treatments?  We will never know unless we do more research like this.  Please donate.

Thank you!

 

References:

Modulation of Blood Flow, Hypoxia, and Vascular Function in Orthotopic Prostate Tumors During Exercise.  McCullough, D.J.,  et al.  J Natl Cancer Inst 2014 Mar 13. [Epub ahead of print]

Therapeutic Properties of Aerobic Training After a Cancer Diagnosis: More Than a One-Trick Pony?  Lee W. Jones, Mark W. Dewhirst.   JNCI J Natl Cancer Inst (2014)dju042doi: 10.1093/jnci/dju042First published online: March 13, 2014

Scientists Explore Effect of Exercise on Prostate Cancer Patients

Walking_2

 

Scientists Explore Effect of Exercise on Prostate Cancer Patients

From the article:

‘In this study, researchers looked at 572 prostate cancer patients and found that those who walked at a faster pace before their diagnosis had more regularly shaped blood vessels in their prostate tumors than those who walked slowly.’

This is initial evidence of a hypothesis that I’ve been advocating, that exercise ‘normalizes’ tumor blood vessels, and that this is a good thing, particularly before chemotherapy or radiation which both work better with more oxygen.  This is contrary to the anti-angiogenic (choke off the blood supply of tumors) dogma that is dominant in oncology.  Although, some anti-angiogenic drugs do temporarily ‘normalize’ tumor blood flow, I think exercise will be found to do it better and also with less side effects, which many of the anti-angiogenic drugs cause.

Rakesh Jain at the Harvard Medical School is a pioneer in this vascular normalization area but with drug interventions.  Therefore, it is encouraging to read the results from this human study that suggest that exercise may be doing the same thing.  There have been some animal studies showing this but to my knowledge, this is the first one from tumors in humans.

For what it is worth, my advice, and what I applied to my own treatments (including exercising during chemotherapy infusion), is to exercise before first cancer treatment (as soon as you are diagnosed, or symptomatic if experiencing a recurrence) in order to improve tumor blood flow, which in theory should improve drug perfusion or the response to radiation.  This should improve treatment response rates, which I hope this study will spur many investigations on.

Keep moving, even if feeling fatigued on some days.  Do not let tumors gain any more advantage than they already have, influence their dysfunctional vasculature growth by normalizing it with exercise!

References

Rakesh Jain:

Animal studies: