Training for Longevity, Not Weight Loss
Up until then, I had never thought of the true importance of exercise: I’d only thought of it as a means to an end—to lose weight and, ideally, to look better in my clothes. Although it is true that exercise can help on both accounts, Isidro allowed me to see that neither of those are as important as keeping the body’s muscles and mitochondria healthy for as long as possible. “The mitochondria are like little batteries that produce the energy that impact vitality,” Isidro explained. “When the mitochondria work well, we feel strong; when they deteriorate, we feel fatigued. It’s also difficult to burn fat, even when we diet. Fat does not only accumulate under the skin, but also in organs, viscera, and even in the muscle itself.”
Here, there is no miracle pill—the only “medicine” proven to improve mitochondrial function is exercise, and especially strength training. Just as a cell phone battery lasts for hours when it’s new but loses its ability to hold a charge, the same thing happens with mitochondria—as we age, we may wake up with energy, but feel exhausted by mid-morning. Thus, we must keep our mitochondria as healthy as possible.
Fast Twitch Fibers and Slow Twitch Fibers
Within the muscle there are slow twitch fibers and fast twitch fibers— slow twitch fibers are responsible for prolonged efforts such as walking; fast twitch fibers are essential for power and speed.
As we age, fast twitch fibers are the first to decline. “Walking improves endurance, but it doesn’t stop the loss of fast twitch fibers. If you don’t train strength, you become sluggish. We see it in older people, who end up walking in short steps because they have lost those fibers. Strength training is the only way to keep them,” Isidro points out. “We gain muscle until the age of 25, maintain it until the age of 35 and, from then on, we start to lose it slowly, accelerating from the age of 50, and even more at the age of 65. There are cases of people in their 70s who maintain the strength of someone sedentary in their 40s or 50s thanks to daily training, proving that this habit can subtract up to 20 years from biological age.”
After all, what you don’t use, you lose. That goes for muscle—but also for bones, the respiratory system, and the pelvic floor. Regular exercise also improves the non-REM phase (deep sleep in which the eyes do not move), and that also decreases with age. Having longer non-REM phases is related to gradual and healthy aging. “Strength training is an investment in health for the future,” Isidro says. “It reduces anxiety and it makes us feel better at all levels. In reality, a healthy body is a perfect body.”
