Exercise and immunity

Exercise is good for the immune system but what about high volume, high intensity, chronic (long-term) exercise?  For cancer patients, a couple of things may be worth considering, but first a few things about immune cells.  In a general sense, cancer is a failure of the immune system to detect and eliminate defective cells, or maybe more accurately, the ability of cancer cells to evade detection from immune cells.

Two categories of immune cells are: innate immune cells; and, adaptive immune cells.  Natural Killer cells (NK cells) are a part of the innate immune system and they respond quickly to tumor formation and virally infected cells.  T-cells are a part of the adaptive immune system.  T-cells remember previous invaders, and cancer, and respond faster the second time to the same invader.  Moderate intensity exercise and life long aerobic fitness improves aspects of both of these immune cell types.  However, high volume, high intensity, long-term extreme exercise can have negative effects (1,2).

A study (3) followed Ironman competitors training for 6 months prior to the event and for a few weeks afterwards.  The researchers found that by the end of study period the ratio of  some T-cell subtypes changed to a composition that an older person is more likely to have.  Naive T-cells, which are highly responsive mature T-cells, decreased, while terminally differentiated T-cells (senescence) increased.  Terminally differentiated T-cells are not as ‘nimble’ as naive T-cells in responding to invaders, and the ratio between the two can change as one ages – more terminally differentiated T-cells accumulate and less naive T-cells are found.  This change is thought to make the elderly more susceptible to infections.  However, increasing aerobic fitness can lower the proportion of age-related senescent T-cells and increase naive T-cells, regardless of age (4), but maybe only to a point, as elite endurance athletes are known to get more upper respiratory infections and changes in immune cells are thought to play a role in this (5).

streaming blood cells

Another piece in this exercise puzzle is a virus, Cytomegalovirus (CMV).  CMV is a common herpes virus infecting approximately 50% of American adults, and that percentage increases with age.  CMV affects the exercise response of NK cells, increasing their numbers and cytotoxicity (killing ability).  However, that changes at exercise intensities eliciting a blood lactate concentration of 4 millimoles, which is about +15% of the blood lactate threshold (as defined by Weltman, A., 1995).  This is an intensity that many endurance athletes periodically train at in order to improve performance – tempo runs for marathon runners are an example.  After exercise that induces 4 millimoles blood lactate, NK cell numbers and cytotoxicity are decreased, but not in healthy individuals, only in CMV infected individuals, and regardless of sex (6).

So what does this mean for cancer patients wanting to do a triathlon, marathon, or ultra?  Right now there isn’t enough evidence to change the general American College of Sports Medicine (ACSM) guidelines of 150 minutes per week of moderate intensity exercise or 75 minutes per week of vigorous exercise.  Although a recent breast cancer study (7) found that 300 minutes per week of moderate intensity exercise was best for post-menopausal breast cancer patients who were not on hormones.  Surprisingly, another study found that higher levels of cardiorespiratory fitness was associated with higher risk of prostate cancer (8), the CMV status of those subjects was not reported and may not be known.  Outside Magazine recently did an article (9) on the deleterious effects ultra-marathons has had on some participants.  Perhaps CMV status or changes in T-cell proportions may be emerging as important markers to follow.  Exercise can help protect us against infection and fight tumors but that does not also mean greater amounts of exercise is better.  Until more evidence is presented, the ACSM exercise recommendations, as generic as they are, appear to be about right for cancer patients, and maybe particularly for those who are CMV positive.

For more in-depth information about exercise and immunity, a couple of recent articles are worth reading (10,11,12), if you can get full access (12).

  1. Special issue on exercise immunology: Current perspectives on aging, health and extreme performance. Richard J. Simpson, Jos A. Bosch. Brain Behav Immun. 2014 Jul;39:1-7.
  2. Is immunosenescence influenced by our lifetime ‘‘dose’’ of exercise? Jmes E. Turner. Biogerontology (2016) 17:581–602.
  3. The impact of 6-month training preparation for an Ironman triathlon on the proportions of naïve, memory and senescent T cells in resting blood.  Coagrove, C., et al. Eur J Appl Physiol (2012) 112:2989–2998.

  4. Aerobic fitness is associated with lower proportions of senescent blood T-cells in man.  Spielmann, G., et al.  Brain, Behavior, and Immunity 25 (2011) 1521–1529.

  5. Upper respiratory tract infections and exercise.  D.C. Nieman. Thorax. 1995 Dec; 50(12): 1229–1231.
  6. Acute exercise preferentially redeploys NK-cells with a highly-differentiated phenotype and augments cytotoxicity against lymphoma and multiple myeloma target cells. Part II: Impact of latent cytomegalovirus infection and catecholamine sensitivity.  Bigley, A.B., et al. (Article in Press) Brain, Behavior, and Immunity xxx (2015) xxx–xxx.

  7. Effects of a High vs Moderate Volume of Aerobic Exercise on Adiposity Outcomes in PostmenopausalWomen. A Randomized Clinical Trial.  Friedenreich C.M., et al.,  JAMA Oncol. doi:10.1001/jamaoncol.2015.2239.

  8. 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. doi:10.1001/jamaoncol.2015.0226.

  9.  Running on empty.  Meaghan Brown.  Outside, June 12, 2015.
  10. Human cytomegalovirus infection and the immune response to exercise. Simpson, R.J., et al., Exerc Immunol Rev. 2016;22:8-27.
  11. Does Regular Exercise Counter T Cell Immunosenescence Reducing the Risk of Developing Cancer and Promoting Successful Treatment of Malignancies? James E. Turner and Patricia C. Brum. Oxidative Medicine and Cellular Longevity Volume 2017, Article ID 4234765, 18 pages.
  12. Mobilizing Immune Cells With Exercise for Cancer Immunotherapy. Simpson, R.J., et all., Exerc. Sport Sci. Rev., Vol. 45, No. 3, pp. 163–172, 2017.
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Sweat the little things

Interior of a corridor with passenger lift

Don’t sweat the little things!

I don’t like waiting … waiting for results, waiting in lines, waiting in traffic, or waiting for elevators.  Regarding the latter, if I’m only going 1-3 flights, stairs are often quicker anyway, plus, I feel like I’m doing something pro’active’ for my health.  A typical flight of stairs might be 16-20 steps, that’s 8-10 repetitions lifting my entire body weight with each leg.  Do this a few times a day, all year-long, as a habit, and it can help maintain leg strength and muscle mass.  Consistently taking the elevator can contribute to loss of leg strength and muscle mass.  Use it or lose it – just like muscles that atrophy from lack of use while in a cast.

A hidden downside to losing muscle mass is that it can contribute to weight gain, fat weight.  Muscles are good calorie burners, when used, if not used, they atrophy.  If one continues eating what they normally do, they will gradually put on weight, because less of the calories consumed will being burned by muscle, so the unused calories get stored as fat.  Initially, this small amount of weight may hardly be noticeable, but after a number of years it can be substantial, affecting health and quality of life.  This makes climbing stairs more tiring, which can perpetuate elevator use and de-conditioning.

Major lifestyle changes, including exercising or the lack thereof, can start this way.  Don’t overlook the little things in a day – like taking the stairs or shopping –  embracing these small physical tasks can lead to change.  Shopping provides another simple opportunity to make a small change.  Park farther away from the doors rather than waiting for a spot up close, or, return your cart.  This may seem trivial, and in terms of calories burned, it may be, but it helps change the habits of our mind, habits which often prevent us from getting out the door for walks or other forms of exercise.

schnäppchenjagd

During chemotherapy, stairs served as my unofficial barometer of drug efficacy.  Prior to my cancer diagnosis I found myself getting tired after going up a single flight of stairs, my quads would burn as if I had just run up a hill.  This was a big warning sign that something was wrong with me.  Each day after starting chemo I would walk up stairs to see how my legs reacted, after a few days I notice a significant difference – my quads did not burn after getting to the top.  I knew then that the drugs were working, they were killing the cancer and I started to regain the weight I had lost from cancer related muscle wasting (cachexia).  For cancer patients with balance issues and wanting to use stairs, having someone assist you would be a good idea, certainly, use the handrail.

conceptual design representing steps to reach success

For those cancer patients accustom to exercising, yet finding themselves preparing for cancer treatment, in the midst treatment, or recovering from it, they might have to lower their exercise expectations.  I’ve talked with a number of cancer survivors frustrated about feeling lousy during workouts, or unable to complete a workout like they could before cancer.  First, I commend them for continuing to exercise throughout their cancer experience.  However, cancer treatments can have a significant effect of on the body – anemia, muscle weakness from anti-inflammatory steroids, lymphedema, surgical pain and tightness, neuropathy in the hands and feet, and the yet unknown sources of treatment related fatigue.  In spite of these treatment related obstacles, many cancer patients do exercise, and some quite a lot.  However, returning to normal gradually, or with different strategies, may be in order rather than jumping right back into their old workout routine.

Runner athlete running on escalator stairs.

One strategy I and others have found helpful, and has long been touted by former US Olympic marathoner, Jeff Galloway, is walk/run.  For me, building up to walking 4.2 miles per hour at 11% grade on my treadmill, a good workout in itself, became physically awkward, running seemed like it would be more comfortable.  However, starting out running a little bit at a time was easier than trying to cover 3 miles all at once right out of the gate.  I used walk/run, beginning with walking 100 meters, then running 100 meters.  That soon progressed to 200 meters, 400 meters, then eventually 3 miles straight, and soon I was back to my normal running routine.  Rest/exercise, coast/pedal-paddle-row, float/swim, etc., could be applied to other activities.

A number of cancer survivors have returned to the highest levels of competition as professional athletes: tennis players Ross Hutchins and Alisa Kleybanova; hockey players Mario Lemieux and Saku Koivu; major league pitchers Jon Lester and Dave Dravecky; and runner Gabe Grunewald; among many others.  The fitness demands of those sports are significant, yet their bodies recovered, and so can yours, probably not to the level of those professionals, but to a level where you are not confined to the couch.  Little things can add up!