Before the curtain falls: a jaunt into gerontology

When I wrote the article on age factors my friend P. Motis (an excellent decathlete, when we were young, and one of the first greek athletes to high-jump in the Fosbury style) complained (jokingly) that my article which quantified the decline of older athletes was depressing. Well, today I am going to go one step further: what happens to athletes when they get really old. (I am aware that the notion of "old" is a relative one. Here I will be using it in its wider acceptance, i.e. referring to persons of at least 65 years of age).

This post of mine was inspired by the recent IAAF guide to sports nutrition published in the International Journal of Sports Nutrition and Exercise Metabolism. I started reading an article on the nutrition for master athletes and was sent to an article by H. Tanaka and D. Seals where they discuss the decline of performance with age. They present several curves showing the dependence of running time (for 10 km and the Marathon) on age. 

Unfortunately the running time is not a good indicator over such large spans (although it is the main thing of interest to the athlete). If one must make a rigorous analysis one must refer to the energetic cost of the activity and when one deals with running the mean velocity is a good representation thereof. Thus I have taken the men master's records over 1500 m, computed the mean velocity and plotted it as a function of age.

The dip, Tanaka and Seals are talking about, is definitely there. Ageing champions manage to contain the damages of age up till roughly 75 years but then things start going south. How do Tanaka and Seals explain this? In their analysis (presented in a review which appeared in the Journal of Applied Physiology in 2003, volume 93, pages 2152-2162) they argue that this sharp decline should be attributed to a reduction in maximal oxygen consumption, what physiologist call the maximal aerobic capacity (VO2max) and which is intimately related to the energetic cost of the exercise. They present an interesting graphic of the dependence of the VO2max on age: 

The apparent greater rate of decline for endurance-trained women compared to the sedentary ones is somewhat misleading. Once one computes the percentages of decline for the two populations the rates become comparable, just as the maximal heart rates observed. 

Tanaka and Seals formulate the hypothesis that the greater absolute rate of decline in VO2max in endurance-trained adults is mediated by the greater decline in maximal stroke volume and, therefore, the maximal cardiac output.

But there is another effect contributing to the sharp decline of performances, the reduction in the exercise velocity at the lactate threshold. (The lactate threshold is defined as the exercise intensity at which blood lactate concentrations increase significantly above the baseline). However it seems that the reduction in the lactate threshold is more pronounced for middle-aged athletes and is not the main cause of the nosedive in performances after 80.

One interesting conclusion of these findings is that if one wishes to maintain an as high as possible VO2max one should devote oneself to higher-intensity aerobic exercises. They have the accrued benefit of maintaining a high lactate threshold.

I am aware that this statement is at odds with the current recommendations which advocate participation in low-intensity aerobic activities for ageing persons. However I think that it is the best strategy in order to compress morbidity, in the words of J.F. Fries (you can find his seminal 1980 article on he subject in The  New England Journal of Medicine, volume 303, pages 130-135). The objective is to extend the adult vigour far into a life span (which appears to be more or less fixed) and compress the period of senescence as near as possible to the end of life. Vigorous exercise is essential in maintaining general health and quality of life.

Having presented the bad news for endurance-based disciplines I asked myself whether the sharp decline observed for middle- and long-distance running was present in all athletics events. I remembered my post on a model on the dependence of the performance on age where I was able to fit the data on the record of men's high-jump as a function of age. The model did not go beyond 70 since the physiological data available did not extend beyond this age. However the world record was available up to the age of 100 and did not show any substantial dip. I decided thus to look up the world records for men's long jump, in the master category. They are represented in the graphic below.

The straight line corresponds to a fit over the ages 40 to 90. It is amazing that all records appear to lie on the line. (The explanation for the one point clearly above the line for 35-year old athletes is that it is due to the 8.50 m performance of Carl Lewis and Larry Myrricks). It is really impressive that only at 95 do we see a dip and, moreover, the 95-100 line is roughly parallel to the 40-90 one and not plummeting like the velocity one. So most probably, and given that nothing similar is observed in high jump, the decrease in performance is probably due to the fact that it is difficult to find athletes in this age bracket. What is the possible explanation of this? The two jumps are essentially based on anaerobic processes and strength and it is my feeling that for these two physiological factors the decline is regular without any significant sudden drop. (Unfortunately most physiological studies stop at 80 and thus I could not find any data in order to support this statement).

I know, those are not very good news, but, at least, one has up to 80 before seeing any noticeable decline. What happens after that, well, if one is lucky to reach that age in good health able to participate in masters' competitions one should be content with this, and not care much about the dip in performances.