Older athletes: resist the aging process!

A famous 1970s American auto racer and stuntwoman called Kitty O’Neil Collins – nicknamed ‘the fastest woman in the world’ – was once asked about the impact of aging on her ability to perform stunts. She replied pithily that “Aging seems to be the only available way to live a long life!” She was right of course, and understood that the inevitable process of aging is something that all athletes have to come to terms with as the years tick by.

The impact of aging on performance

There are a number of physiological changes that take place as we age, and while lifelong top-quality nutrition and exercise can dramatically slow these changes, as each decade passes, maximum performance potential declines (for a more detailed discussion on aging and performance, readers are directed to this article). Although there are large individual variations, as a rule of thumb, peak performance is typically attained around 25-30 years of age, after which athletes will experience a steady decline in maximal exercise capacity, no matter how long or intensely they train.

The reason for this decline is primarily due to a combination of reduced muscle mass combined with decreased cardio-respiratory (heart-lung) function. We know this to be the case because over the years, numerous studies have shown the following^(1-4):

*Strength and speed tend to peak at the earlier end of this age range while endurance peaks in the later range.
*During early middle age (40 to 50 years of age), physical activity declines resulting in a typical 5-10kg of body fat gain. Moreover, this decline continues into old age.
*Maximum heart rate also declines with age and (partly because of this fact) maximum aerobic capacity also declines by about 1% per year (although this decline may be stemmed with regular training).
*The mass of fast-twitch muscle fibres (needed to produce strength and power during high-intensity exercise) is most pronounced during the 30s, where studies have shown a decline in power of 3% per annum with 1% per annum every year thereafter for both men and women.

Muscle mass and aging

One of the most striking age-related changes that take place as the years tick by is a steady loss in muscle mass and muscle fiber function, particularly after middle age. In sedentary older adults, the decrements in the amount of skeletal muscle (and therefore strength to perform day-to-day tasks) may be large enough to compromise independence and quality of life⁽⁵⁾. But age-related muscle mass loss isn’t the only problem; research shows that in the muscle fibers that remain as we get older, function tends to reduce – ie the contractile force generated per fiber tends to decline with age.

This functional loss in muscle fibres is thought to be partly or even largely explained by a process called ‘muscle fiber denervation’⁽⁶⁾. Muscle fiber denervation seems to occur either through the breakdown of the neuromuscular junctions, reducing the ability of electrical signals to stimulate muscle contractions, or through the death or muscle motor neurons or both. Interestingly, it seems that regular pulses of electrical signals passing through the motor neurons and muscle fibers (ie vigorous exercise) is required for maximal preservation of neuromuscular function as we age. Indeed, inactivity is not merely an innocent bystander, but plays an active role in denervation by increasing the production of chemicals and hormones that are hostile to the ability of neurons to survive the aging process⁽⁷⁾. This really is a case of ‘use it or lose it’!

Combating muscle mass and muscle function loss

The importance of minimizing muscle mass losses as we age cannot be overstated – not only for athletic performance but also health. Given this importance, how can older athletes deal themselves the best physiological hand possible to preserve maximum muscle mass? The answer of course is good nutrition and (as implied above) the continuance of vigorous exercise into older age.

Regarding nutrition, a number of studies have concluded that as we age, consuming enough protein to preserve muscle mass becomes more important than ever. For example, a recent review study surveyed the recent research on nutrition, muscle mass and aging, and concluded that older adults (whether athletes or not) should increase their intake of protein above the recommended dietary allowance (ie consume more than the 0.8 grams per kilo of bodyweight that is commonly cited)⁽⁸⁾. It also concluded that a special effort should be made to increase the intake of omega-3 essential oils (EPA/DHA – found in oily fish such as salmon, herring, mackerel, sardines, trout etc). In particular, it seems that a combination of adequate protein and omega-3 intakes stimulates muscle synthesis by boosting an important signalling molecule called ‘mTORC1’, which has the ability to upregulate gene activity associated with muscle growth (see this article).

What kind of protein and omega-3 intakes should older adults be aiming for? Observational studies suggest protein intakes from ranging from 1.0 to 1.6 gram per kilo of bodyweight per day can promote greater muscle strength and function, with those who are physically activity tending towards the upper end of this range⁽⁹⁾. Interestingly, these same studies also favor animal protein sources over plant sources. Regarding optimum omega-3 intakes, studies where older or elderly people (both sedentary and active) were supplemented with a total of 3000mg per day of DHA/EPA and where the EPA intake in that combination was 800mg per day or more, have shown positive effects on strength and muscle mass^(10,11). Where consuming plenty of fatty fish (2 or 3 days per week) is not an option, omega-3 supplementation should be considered as an essential part of optimum nutrition for those of advancing years!

The heavy weights option

When it comes to exercise and muscle mass preservation in later years, you will not be surprised to learn that strength training is vital. What’s more, studies show that vigorous strength training using relatively heavy resistance is essential, and much better than cardiovascular training alone or gentle/moderate-intensity resistance training (as used to be thought)⁽¹²⁾. Instead, the optimum scenario involves a combination of cardiovascular training and heavy strength training. And just as the case in younger athletes, older athletes (and their sedentary counterparts) need to adhere to the basic strength-training principles when trying to build or maintain muscle mass⁽¹³⁾:

·       The training load applied needs to overcome habitual levels of strength – ie the muscles need to be pushed or overloaded to generate a training adaptation.

·       Training needs to be specific and adapted to the individual – ie to build leg muscle/strength, you need to train the legs and set a program that is appropriate for the individual’s current level of fitness.

·       Training loads (intensity, volume) need to be adjusted/increased over time (while allow periods of recovery) in order to continue to provide a growth stimulus as muscles adapt.

 In a comprehensive review study on this topic, researchers likened the use of heavy strength training as a way to make the slope of age-related decline more shallow, therefore prolonging mobility and health well into old age (see figure 1).

Figure 1: Optimum training approach to slow muscle mass loss and maintain health*