Age is just a number, or is it? While we should not fear getting older, we must also face the facts that our bodies at 65 do not function as they did at 25. Though we tend to discover new creaks and cracks in our joints throughout our life, this does not mean that we need to sacrifice our performance when it comes to sport.
Simply hoping that you will be the anomaly to the age factor is not your best option. It is important to understand what will occur throughout life in regards to your physiology to help you prepare and alter your training accordingly.
Three Primary Indicators of Exercise Performance
When it comes to indicators of performance, the following are the three determinants coaches/sport scientists evaluate:
- Maximal Oxygen Consumption (VO2 Max)
- Lactate Threshold
- Exercise Economy
For a bit of refresher let’s review the above to get an understanding of what will be occurring to each of these with age.
- VO2 Max: VO2 max is your body’s maximum capacity to transport and consume oxygen to produce energy. This value has two measurements: absolute and relative. The absolute value is measured in liters of oxygen per minute, while the relative is measured in milliliters of oxygen per kilogram of body weight per minute.
- Lactate Threshold: your body’s ability to sustain a high fraction of your maximal oxygen consumption during submaximal exercise
- Exercise Economy: measured as the steady-state oxygen consumption while exercising at a specific submaximal intensity below lactate threshold.
To further break it down, we will look at VO2 Max: Your VO2 max is determined by the Fick Equation:
VO2 = 𝗤 x (a-vO2 diff)
- The 𝗤 represents your Cardiac Output (expressed as L/min) multiplied by your Arteriovenous Oxygen Difference (a-VO2 diff).
- Cardiac Output is the product of your Stroke Volume (volume of blood pumped by the left ventricle with each beat) multiplied by your heart rate.
- Arteriovenous Oxygen Difference represents the amount of O2 that is taken up from 100 mL of blood by the tissues in 1 cycle of the circuit.
Woo okay, so what does all this have to do with getting older and performing? Well, studies have shown that out of the three indicators of exercise performance, the primary mechanism for a decrease lies within your VO2 max. (Joyner, 1993; Coyle, 1995). This decrease in your VO2 is due to changes in the following:
- Decrease in Maximal Stroke Volume
- Decrease in Heart Rate (maximal heart rate too)
- Decrease in your Arteriovenous Oxygen Difference (a-vO2 diff)
As discussed previously, your VO2 max is the product of both cardiac output and your a-vO2 diff. Your cardiac output is the product of your stroke volume and heart rate. If we put these facts together, all of the variables that comprise your VO2 and Cardiac output take a hit as we get older. (Cue the violins.) According to Robergs and Roberts (1997), a 30% decrease in stroke volume between the ages of 25-85 years old contributes most to the age-related decreases in VO2max. The most notable change in cardiovascular function is observed in the decrement of maximal oxygen consumption with advancing age; 10% decrease per decade after 30 years old (Heath et al. 1981; Buskirk & Hodgson, 1987; FitzGerald et al. 1997; Tanaka et al. 1997; Eskurza et al. 2002; Pimentel et al. 2003).
While VO2 max may have the most significant decrease in performance due to age, a decrease in your lactate threshold comes in second. Lactate threshold (LT) is typically measured in a lab where this level defines the exercise intensity at which blood lactate concentration increases significantly above baseline. When it comes to age and your LT, absolute work rate or running speed at your threshold decreases with advancing age in endurance athletes (Iwaoka et al, 1988; Maffulli et al, 1994) These decreases do not directly correspond with decreases in your VO2 max, and the rate of loss is much less severe.
Exercise economy is determined by a number of physiological factors that include muscle fiber type. In regards to endurance sports, the percentage of type 1 muscle fibers are associated with increased exercise economy. With regards to aging, well-trained masters athletes have a similar muscle fiber distribution to performance-matched younger athletes (Coggan et al. 1990.) It has also been shown through a 20-year longitudinal study that maintenance of strenuous endurance training, the muscle fiber distribution did not change with trained Masters athletes (Trappe et al. 1995.)
Strength Training Benefits
As we age, the composition of our muscles and bones will change. This is especially true for masters female athletes at post-menopausal ages. Estrogen plays an important role in bone remodeling and keeps the decline of bone loss in check. After menopause, the protective effects of estrogen are lost and women can experience bone loss at a rate of up to 2-3 percent per year. Strength training is beneficial for this population because it stresses the musculoskeletal system which stimulates the remodeling process of the bones. This helps to mitigate further bone loss and helps to build bone density in older individuals.
Strength training is especially important for athletes between the ages of 40 and 60 and it is paramount to include in training all year for all athletes over 60 years of age.
In addition, it can be beneficial to pay special attention to postural exercises that can target areas such as the upper back to strengthen the muscles between the shoulder blades which helps prevent sloping shoulders and rounding of the upper back. Balance exercises can also be helpful for older athletes to reduce the risk of falling.
When it comes to recovery, the timing of sessions will be paramount. It was great when you could do back-to-back hard leg-burning sessions in your 20’s, but those types of training days will not be the best now. When it comes to structuring a schedule, be cognisant of placing back-to-back hard workouts. As the legendary athlete, Ned Overend said about winning XTERRA World Championship titles at age 42 and 44 said, “what used to be a 12-week training schedule now takes 16 weeks to complete because I have to include more recovery between the harder sessions. I still do all the same work, but I have to include strength training year-round and take a couple of extra days between harder sessions.”
Generally speaking, master’s athletes will take a longer period of time to recover than younger athletes. Another key point to stress about recovery/performance and aging is that your plate of responsibilities is most likely more full than years previous. Perhaps you have a family, a full-time job, and additional obligations that require your time and energy. Ensuring that you are not running yourself into the ground is more important than ever since you may not have the time to fit 10 different recovery modalities after training. Be sure to nail post-session nutrition, mobility, and as always: sleep!
What does this mean for all of us getting older? To put it simply: use it or lose it. While we cannot control all of the changes that will occur to us physiologically, we can do our best to mitigate the rate of loss by continuing with a good training regimen, strength training, and adapting our recovery. As is important with racing and life itself, focusing on the pieces we can control is our best offense and defense when it comes to the battle of age. Having a good understanding of how your body is feeling can help you determine if today you give yourself the green light, or to back off. It is commonly said that age is just a number. Don’t let that number define your infinite possibilities.