Your body changes through the years. Should your diet?
Written by: Matt Fitzgerald
The percentage of runners over age 45 has increased by more than 30 percent in the past five years. This is due in part to the fact that the sport’s retention rate is growing: the number of people who have been running for 10 years or more has also increased substantially in recent years. Nutrition is critical to running well over the long haul.
Older runners do not have nutritional needs that are substantially different from those of runners in general. What is different about older runners, however, is that they can’t get away with not eating properly they way a younger person might. In other words, the nutrition guidelines that are important for younger runners are even more important for older runners.
A diet that is laden with antioxidant-rich fruits and vegetables will slow the aging process and its effects on performance. This is true because aging is caused in part by free radical damage to body tissues. As the body ages its antioxidant capacity—that is, its capacity to protect itself from free radicals—decreases, and antioxidant capacity, in turn, is linked to endurance performance. Supplementing a plant-based diet with additional antioxidants may yield further benefits. A study conducted by researchers at UCLA and published in the Journal of the International Society of Sports Nutrition provided intriguing evidence that antioxidant supplementation may be especially helpful to older endurance athletes.
The subjects of the study were 16 male cyclists between the ages of 50 and 73 years who trained at least four hours per week. Half of the subjects were randomly assigned to take an antioxidant supplement daily for three weeks while the others were given a daily placebo. All of the subjects engaged in their normal training during the intervention and all underwent performance testing at the start of the intervention, again after one week, and one last time after three weeks.
At one week, the subjects receiving the antioxidant supplement exhibited a 16.7 percent increase in anaerobic threshold. This increase was almost completely maintained at three weeks. There was no change in anaerobic threshold in the control group. The supplemented subjects also exhibited an increase in power output at anaerobic threshold while the control subjects did not.
Another issue of concern to older runners is recovery nutrition. Older runners are more susceptible to muscle damage caused by eccentric muscle contractions (muscle contractions wherein the muscle lengthens as it contracts) and are not able to repair this damage as quickly between workouts. You can reduce muscle damage during running by drinking a good sports drink. You can also greatly accelerate muscle tissue repair by consuming a recovery drink containing carbs and protein within 45 minutes of completing a run. But whereas a 20-year-old runner might be able to stray from these guidelines somewhat without noticeable consequences, a 50-year-old runner will almost certainly compromised his or her recovery severely.
Nutrition habits play an important role in maintaining muscle mass and strength. The older a runner gets the less he can take his nutrition habits for granted in this regard. After age 35 we tend to gradually lose muscle mass, mainly because we produce smaller amounts of anabolic hormones such as growth hormone. Adequate protein intake is essential for muscle maintenance. Research has also shown that athletes who practice correct recovery nutrition habits are better able to maintain muscle mass.
Proper nutrition alone is not enough. Unless you combine adequate protein intake with exercise, you will not succeed in slowing aging-related muscle atrophy. Running is exercise, of course, and running has been shown to delay and slow muscle loss in older runners. But to really do the job properly you must supplement your running with strength training. Again, younger runners can likely avoid strength training and not lose muscle mass. (For injury prevention, strength training will benefit you no matter what your age.) But once you pass age 35, strength training becomes truly indispensable for maintaining muscle mass–along with adequate protein intake and correct post-workout nutrition habits.
Our daily energy needs also tend to decrease gradually as we age. This is primarily an effect of a simultaneous decrease in the resting metabolic rate (RMR), which in turn is partly due to muscle loss. One reason most adults gain weight steadily throughout adulthood is that they continue to eat the same amount despite the fact that their RMR is going down. This phenomenon does not occur in runners and other endurance athletes, however. In a study at the University of Colorado, female runners and swimmers aged 50-72 had the same RMR as women aged 21-35, whereas the RMR of sedentary women aged 50-72 was 10 percent lower on average.
So the bottom line is that if you stay in shape throughout your life, the amount you eat should not have to change.
Matt Fitzgerald is the author of Iron War: Dave Scott, Mark Allen & The Greatest Race Ever Run (VeloPress 2011) and a Coach and Training Intelligence Specialist for PEAR Sports. Find out more at mattfizgerald.org.