Paul analyzes several papers that talk about biochemically how the body may be impacted by endurance exercise leading to cancer risk. And he says may
But he ends with this:
I don’t want to exaggerate the risks of endurance sports. With the exception of melanoma , there isn’t a clear increase in cancer incidence among marathon runners. And if this post seemed a bit tortuous, it’s because there’s no simple “smoking gun” pathway connecting endurance exercise to cancer.
On the other hand, endurance exercise is probably not as healthy, in terms of cancer risk, as shorter-duration activities. Also, the risk may rise substantially on high-carb or wheat-based diets. There are at least a few plausible mechanisms, not all of which I’ve discussed here, that might connect endurance exercise on grain-based high-carb low-fat diets to cancer.
Dr K has talked about endurance athletes having shorter telomeres and advocates sprinting only...400m max.
It must be that all the biochemistry Paul goes through results in shorter telomeres which is a marker of a potential shortened life.
Is there causation or a corolation? What do you think?
Will you alter your exercise regime from less endurance to shorter exercise. Or is the high of endurance exercise too good to give up?
Dexter the data is pretty clear......I dont need a RCT to tell me endurance exercise kills us. Cause it does. HIIT is hormetic and helpful. I think Paul has been reading and reading well. He is a friend of mine on FB and I have been lobbing grenades about endurance exercise for a long time. If you enjoy it.....fine. But I am in the business of advising. And based upon what we know now.....the advice is it will harm you.
Is there correlation? We do have some anecdotal accounts. Grete Waitz (cancer), Alberto Salazar (multiple heart attacks ... but bad genetics and hypertension, according to him), Jimmy Fixx, etc. Countless others, according to those who support the theory.
But the best anecdotal evidence I've heard is this one by Kent Rieske: Why is it always the Marathoners who are collapsing and dying, not those in the stands watching the sport who outnumber the runners, who would presumably be less fit cardiovascularly?
Maybe there is something to this, eh? This is probably the best casual evidence based purely on cursory observation.
But whatever happened to the simple theory that endurance sports result in chronic inflammation throughout the body, due to elevated cortisol, insulin, etc., and that this inflammation is the start of all modern diseases: diabetes, CVD, cancer, and autoimmunity? If the atheletes are eating carb-heavy diets, and if the carbs are not from safe starches but include sugar and fructose (horrors), is it so far-fetched that they're falling by the wayside with cancer and CVD prematurely?
Sugar/Fructose + Refined Carbs + Oxidative Stress from Endurance Exercise ==> High Cortisol + High Insulin => Chronic Inflammation => CVD and Cancer
aren't biomechanics and overall physical prowess a bit of a factor? i mean, the chicago marathon used to pass my house, and we were at "the wall", mile 20 and it was amazing to see how different people's bodies handled running. We used to pull out the lawn chairs and a bloody mary and watch them go by. One person would seem like they were putting out no effort whatsoever and simply gliding along, and the person next to them going the same exact pace looked like they were giving the hardest effort of their life. It also always made me ask myself "who is doing the harder effort? the front runners who do this in 2 hours with gliding biomechanics or the middle of the road person who works hard at a slightly lower but bouncier, more jarring intensity for much much longer?" Personally, I always though the guy who was there for 4-5 hours had a much harder race than the guy who could do it in 2.
Most evidence actually shows that endurance athletes adapt well to the oxidative stress from their training and racing. There is a decline in DNA damage after Ironman triathlons. See this article for references: