In

the last few posts (here, here and here) I’ve made the point that

as we age the training variable we probably most need to focus on is aerobic capacity

(VO2max), according to the research on aging, as it appears to decline faster than

lactate threshold (Allen, Coggan) and economy (Tanaka, Tanaka). So next we'll examine aerobic capacity a little more closely since it seems to be the primary

limiter for most of us (Hawkins, Wiswell).

Note,

however, that this doesn’t mean it is the limiter for all older athletes, especially those who have been in their sport

for a short time, perhaps three years or less. Of course, there may well be

several things, not just aerobic capacity, that are holding you back when it

comes to improving your endurance performance as you get older. A likely

candidate for this list is your body weight. Another related physical matter is the loss of muscle mass. I'll come back to these shortly.

For

now we’ll take a bit deeper look at aerobic capacity. Let’s start by getting a handle on

what it means.

Aerobic

capacity is determined using this formula:

VO2max = ml O2 / kg / min

The

common way VO2max is determined in a lab is to have you run (or bike) starting

at a low intensity with increases every few minutes until you can no longer

continue. It isn’t fun. But it produces a number – your VO2max – which is an

indicator of your endurance fitness. At your peak output, just before failure,

the amount of oxygen you’re consuming per minute (“min”) is measured using a

device hooked up to a mask over your nose and mouth in order to measure the gases you are breathing in and out. The

measured oxygen component of those gases is referred to

as “ml O2” (milliliters of oxygen).

A

computer, which is a part of the testing device, divides your ml O2 per minute

by your body weight in kilograms (“kg”). If you’ll recall from your elementary school

math class, whenever you divide two numbers, as the denominator (the number

you’re dividing by) increases, the quotient (VO2max in this case) decreases. So

what does that mean? As your body weight increases, your aerobic capacity

decreases. This should be obvious to you. You’ve probably had times in your sport

career when you’ve put on a bit of weight. At those times running, cycling or

cross country skiing uphill has been harder. If you lost weight it became

easier. Both of these are reflections of your aerobic capacity at the time.

All

of this means that there are two formula-based determiners of your aerobic

capacity – body weight and ml O2 used (“min” is constant). Lower weight means

higher VO2max. Higher weight means lower VO2max. Simple.

The

other determiner is not so simple. This is the component of aerobic capacity

that has to do with how much O2 you used at peak, sustained effort. It includes a whole bunch of stuff such as how much blood your heart

pumps per beat, how many red blood cells you have to carry the oxygen, the

number of tiny capillaries in the muscles to deliver the blood, the amount of

aerobic enzymes in the working muscles to “pull” the oxygen out of the blood into the muscle and convert it to energy, and much more. (Note that I didn’t mention lung capacity.

That only becomes an aerobic capacity issue if you have a lung-related disease

or condition.)

Other

than losing weight, there are two primary ways to improve the oxygen-using components of aerobic capacity with

training. One is by doing a lot of long workouts. The other is by training with

high intensity. As an older athlete who has been training for years and years,

more long, slow distance workouts aren’t going to do much for you in this regard. That brings

us back to high-intensity training which, if you’ll recall from my last post, was shown by Trappe, Costill and

associates to be the best way to preserve aerobic capacity as we age.

In

my next post here we’ll examine the details of high-intensity training to

improve aerobic capacity and a few of the adjustments that are usually necessary

as we age.

References

Allen

WK, Seals DR, Hurley BF, et al. 1985. Lactate threshold and distance-running

performance in young and older endurance athletes. J Appl Physiol 58:1281-4.

Coggan

AR, Spina RJ, Rogers MA, et al. 1990. Histochemical and enzymatic

characteristics of skeletal muscle in master athletes. J Appl Physiol 68:896-901.

Hawkins S, Wiswell R.

2003. Rate and mechanism of maximal oxygen consumption decline with aging:

implications for exercise training. Sports Med 33(12):877-88.

Tanaka H, Seals DR. 2003. Invited

review: dynamic exercise performance in masters athletes: insight into the

effects of primary human aging on physiological functional capacity. J

Appl Physiol

95(5):2152-62.

Tanaka H, Seals DR. 2008. Endurance

exercise performance in masters athletes: age-associated changes and underlying

physiological mechanisms. J Physiol

586(1):55-63.

Trappe

SW, Costill DL, Vukovich MD, et al. 1996. Aging among elite distance runners: a

22-year longitudinal study. J Appl

Physiol 80(1):285-90.

Wiswell RA, Jaque V, Marcell TJ, et al. 2000.

Maximal aerobic power, lactate threshold, and running performance in master

athletes. Med Sci Sports Exer

32:1165-70.

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