I will use the standard marketing style — “Yes, but it’s not what you think!” In order to effectively answer your question, I think we’d need to define fanatic and that of course is subject to interpretation. The obituaries are peppered with athletic superstars dying before their age. Grete Waitz died at 57 of cancer. Jim Fixx died young of heart disease. Micah True, the legendary trail ultra-runner and one of my personal heroes, died in his 50’s with ‘idiopathic left ventricular dilatation’ (a pathologically enlarged heart). But, it is not just long distance runners. Vasily Alexeev, the Russian super star weight lifter, died of heart disease at 69. What people seem not to want to talk about is that, especially endurance athletes, develop dilated cardiomyopathy that predisposes to potentially deadly irregular heartbeats. While I was always loathe to believe that these were nothing more than coincidence, I no longer feel that way, now that I have spoken to several sports medicine docs. I think that very high level endurance athletes in particular, are at risk for this compensatory dilatation that predisposes them to potentially deadly arrhythmias. No one knows for sure though, if they had genetic predispositions, as well to irregular heartbeats or heart disease. In the case of Jim Fixx, who died of garden variety blocked arteries in his late 50’s, we do know his father died at age 43 of pretty much the same thing. So, you could make the argument that running added 15 years to his life, if you wanted.
So, bottom line: “fanatic exercise” is probably not conducive to any survival advantage and probably the opposite.
But, there is stronger evidence that moderate to intense exercise, short of fanaticism, is actually good for you. If one uses telomere measurement as a biomarker for life span, which is getting to be more and more obvious, even to the most hard core nay sayers, there are some interesting studies.
The first is the “German runner’s study” where middle aged (the study, in a throwback to days gone by, said “elderly”, but the average age was 51!) chronic runners who did about 50 miles a week for most of their adult lives, had similar telomere lengths to young sedentary (25 year olds), non-athletes and young athletes training at a similar level. This has been used by just about everyone with an exercise agenda, to justify that agenda. In particular, marathon people love to call them marathon runners, but the study does not even use the word marathon and most marathoners would agree 50 miles/week is pretty low level for a serious marathoner. Triathletes call the German runners triathletes, yoga aficionados say it proves yoga is good for you, and on and on. But that is not what the study said. It says that long term, vigorous activity, in this case 50 miles a week of running, is a telomere preserver. What is not clear is what else these runners did in terms of training. Supplements, hormones, eating, sleeping, etc., etc. It’s common enough to see fit people doing a lot of other things conducive to fitness that are not measured. So basically, when you find a group of people who’ve dedicated themselves to fitness, for that length of time, there is a ton of other stuff they are doing to stay healthy that you are not measuring, making it harder to say “hey, it’s the running that did it”.
On the interval training side of the fence, Elissa Epel released a study that suggested interval type training was really beneficial and associated with longer telomeres. A few problems with that study: the participants averaged 63 years of age, were osteoporotic and self-evaluated their exercise intensity. Nevertheless, there was a clear cut non-chance association with longer telomeres.
Finally, the best ones, in my book, is the “Danish Twin Studies” Mech Ageing Dev. 2011 Nov-Dec;132(11-12):568-72. Leukocyte telomere length and physical ability among Danish twins age 70+.
Bendix L, Gade MM, Staun PW, Kimura M, Jeune B, Hjelmborg JV, Aviv A, Christensen K.
Am J Epidemiol. 2008 Apr 1;167(7):799-806. Epub 2008 Feb 12.
Telomere length and mortality: a study of leukocytes in elderly Danish twins.
Kimura M, Hjelmborg JV, Gardner JP, Bathum L, Brimacombe M, Lu X, Christiansen L, Vaupel JW, Aviv A, Christensen K.
Center of Human Development and Aging, New Jersey Medical School, University of Medicine and Dentistry of New Jersey, Newark, NJ 07103, USA.
The first study looked at both fraternal twins, who are not genetically identical and monozygotic (identical) twins, where genetic variation is not a factor and at least early age environmental issues (basically epigenetics), were the same. They found the fitter member of the pairs had significantly longer telomeres. The next study correlated telomere length with mortality, in a similar population. They found the twin with the longer telomeres was longer lived and the more the difference between the two, the more predictive telomere length and life/death were.
I wish the same group would have done both studies and in all of the above studies there are measurement issues. I wish they would redo everything with the Life Length assay, which would be far more accurate and instructive.
So, there is data. It is just not as strong as we’d like it to be. In our book The Immortality Edge, we recommend interval training in a non-joint damaging way, as the best for people who are just beginning to exercise. For the rest of us, moderation in training load that does not overload the body’s oxidative defenses and does not damage the joints, appears best. Note this does not exclude high intensity exercise. It just puts it in the context of overall training load. We did not discuss the signs and symptoms of overtraining in the book, but you can find them anywhere on the internet. If you want to go hard, find the level where you start to become over trained and back off. As your training tolerance builds, you can push again, looking for the same parameters. If you hit a plateau and can get no more fit than you are at that point, reassess your training methods and programs. It’s rare that an uncoached athlete comes close to their genetic potential, which would be the other reason you plateau.
Personally, I do my highest intensity work in the deep water with a vest – I no longer sprint at the track. I also use an Airdyne and a Versa Climber, both of which are very low or no impact. As far as strength, I favor body weight stuff and my good friend Eddie Baran is the guy you want to see for that: http://gymnasticabs.com/