Fitness is an excellent tool to measure aging as fitness decreases over time. Your fitness level provides a valuable tool in assessing overall health. It is perhaps the best estimate of your risk of death, in particular from cardiovascular events.
Every cell in your body produces energy to function. Every cell also has power plants for energy production, called mitochondria, which make energy. The more regular you exercise and increase your heart rate, the more power plants you have and the better they function. Eating healthy nutrient-rich foods also improves power plant function. Mitochondria mix fuel (fat and sugar) with oxygen to create energy. Spread out all your mitochondrial on a flat surface and they would cover an enormous surface area, nearly three acres in size.
When you run you on a treadmill or pedal a bicycle as fast as you comfortably can we can measure your body’s maximal ability to burn oxygen, specifically measuring the volume of oxygen burned by your mitochondria. Measuring maximum oxygen consumption or the volume of oxygen you can consume (VO2 Max) is the gold standard for fitness testing today.
Over your lifetime, you lose about 1% of your maximum capacity to burn oxygen and produce energy every year. This decline occurs equally with someone who is very inactive and with master athletes; master athletes appear to lose their fitness more slowly, but only because they have a much larger reserve of function to lose to start with.
The loss in mitochondrial function is one of the most important measures of aging. Mitochondrial dysfunction is also one of the first signs that you might be developing diabetes or losing mental function. A rapid decrease in VO2 Max over time could indicate that you suffer from accelerated aging and would signal that you are at high risk for loss in mental function, for diabetes, and for cardiovascular disease. The good news is that a healthy diet and a regular exercise program that combines aerobic exercise with strength training can quickly improve VO2 Max even in very elderly adults.
Measuring VO2 Max annually is easy and safe to do. It is also an excellent way to assess your overall fitness level, your rate of aging, and your future risk for many diseases.