When it comes to endurance training, the term "VO2 max" is often thrown around, typically without any understanding of its actual meaning. To put it simply, your VO2 max is a measurement of how quickly you can utilize oxygen (O2) while exercising at max capacity. Specifically, it measures how many milliliters (mL) of oxygen you utilize per minute (min) of exercise. Generally speaking, your VO2 max measurement is normalized by your weight in kilograms (kg), resulting in a rate measurement in mL/kg/min.
Your VO2 max is a rough approximation of your aerobic endurance capabilities. There are many other factors that will ultimately determine how fast you can run, how far you can swim, or how quickly you can row. But with that in mind, each of these activities require transporting oxygen to your muscles, hence the importance of VO2 max. The better you can transport and utilize inspired oxygen, the better prepared your muscles will be to perform aerobic exercise. Not to mention, there's decent evidence correlating VO2 max with longevity.
You may be wondering what constitutes a "good" VO2 max. It ultimately depends on a number of factors including age and sex. For males <35 years of age, a VO2 max >55 mL/kg/min would be considered pretty good. This shifts as you age and anything >35 mL/kg/min is considered good for males >65 years of age. For females, a good VO2 max would be >50 mL/kg/min and >30 mL/kg/min for females <35 years of age and >65 years of age respectively. To be clear, "good" in this context is somewhere between "average" and "elite".
If you're interested in increasing your VO2 max, thereby increasing your exercise capability and decreasing your risk of chronic disease, there are a number of ways to do so. The simple answer is to exercise. More specifically you should target Zone 2 exercise and interval training. For more information on Zone 2 exercise, check out our post on how to be a more consistent runner on a busy schedule.