The number of people over 50 who exercise regularly and participate in competitive sport is increasing year by year, and their peak performances are often stunning. Recent data have shown that 25% of the older athletes are faster than 50% of the younger ones.
Several studies have shown that with age, master athletes lose their strength and endurance at a much slower rate than sedentary people. As they have also demonstrated that even very competitive master athletes train less than younger ones, scientists are still wondering how much of this decline is due to age and how much to inactivity.
Strength
From the age of 40 you begin to lose muscle mass. The main reason for this is inactivity, but you also start to produce less new muscle proteins. At the same time you gain fat, which means that even if your body weight remains unchanged, the percentage of fat is increasing. This can become a problem, because the strength you need for your daily tasks remains the same. You might therefore reach a point where simple activities, such as getting up from a chair, can become a challenge. However, the good news is that you can increase your muscle mass by strength training, whatever your age.
Cardiovascular function
VO2 max is one of most widely used parameters to evaluate your cardiovascular function. It is the maximal amount of oxygen you can use to produce energy, and it depends therefore on your maximal heart rate, the maximal volume of blood your heart can pump at each beat, and the amount of oxygen your muscles can extract from your blood.
Your maximal heart rate declines by about one beat/min/year, and is best calculated using the following formula: 208- (0.7 x age)
The reduction in maximal heart rate is similar for sedentary people and trained athletes, even though there can be big differences between individuals.
The amount of blood your heart ejects at each systole is called the stroke volume. In sedentary people it declines with age, but in trained athletes it does not change that much. However, as the maximal heart rate decreases, the maximal cardiac output decreases as well.
Studies have shown that the muscles of older athletes can extract more oxygen from blood, which could compensate for the reduced supply.
In sedentary people, VO2max declines by about 1% a year. Scientists agree it also decreases in endurance trained athletes, such as marathon runners, but mainly after 55 years of age. As they have a higher VO2max to start with and lose only the same relative amount as sedentary people, their absolute values continue to be higher.
This is important because a low VO2max is linked to at a higher risk of cardiovascular disease. There is still controversy about how much of this decline is due to inactivity, since even the most competitive master athletes reduce their training regimen as they get older. They do so because they have less opportunities to train, suffer more from aches and pains or need more time to recover from strenuous workouts.
Lactate threshold
The lactate threshold corresponds to the exercise intensity at which your blood lactate levels start to increase sharply. It is usually expressed as a percentage of VO2max. A higher threshold is beneficial, since lactate accumulation is one of the reasons you get tired.
The speed you can run at or the work you can perform at your lactate threshold declines as you get older, but if you express your lactate threshold as a percentage of your VO2max, it does not change. Some studies show it might even increase.
Exercise economy
Exercise economy is the oxygen cost to exercise at a given intensity. It is important for endurance exercise, such as running. Most studies have shown that it does not change with age.
Older runners have a shorter stride, but researchers do not think that this slows them down.
Not only for competitive athletes
Studies show that physically fit older adults live longer and are healthier than unfit ones, and that the more exercise you do, the greater the benefits. They also demonstrate that sedentary individuals who start exercising improve their survival, and that they can increase their endurance and strength whatever their age. It is therefore never too late to start.
References:
Jack H. Wilmore, David L. Costill, W. Larry Kenney. Physiology of Sport and Exercise 2008, Human Kinetics
Hirofumi Tanaka, Douglas R Seals: Endurance exercise performance in master athletes: age associated changes and underlying physiological mechanisms J Physiol. 2008 January 1; 586(Pt1): 55-63
Hirofumi Tanaka, Douglas R Seals: Invited review: dynamic exercise performance in master athletes: insight into the effects of primary human aging on physiological functional capacity Journal of Applied Physiology November 2003; 95(5):2152-2162
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