03/19/2026
What is important in getting and maintaining fitness?
This is a common question I’m asked by patients, family, and friends. I know a healthy, fit me is closer to my best self. I look at fitness like a three-leg stool: strength, endurance, and VO2 max.
Strength is obvious. You should be doing some type of resistance training to maintain or improve muscle mass. One measure of aging and decline is loss of muscle and strength. You can slow this decline with specific strength training. Your ability to maintain a healthy lifestyle as you age is directly tied to your muscle mass and strength.
The second leg is endurance. Endurance is your ability to sustain effort over a longer period. Doing sustained walks, runs, swims, or bikes at a lower heart rate helps build and maintain mitochondria, the body’s energy source. This helps burn fat and control glucose. Staying in this lower zone takes discipline and focus.
The last is VO2 max - the maximum amount of oxygen your body can use during intense exercise. Its decline with age is significant, beginning in the late 20s or early 30s and accelerating after 50, at about 1% per year. Factors like reduced muscle mass, lower cardiovascular efficiency, and lifestyle (sleep, alcohol, diet) contribute. You can train VO2 max with steady-state work, but the most important training is harder intervals that push your heart rate higher. VO₂ max intervals are most effective at 90–105% of max heart rate, lasting 3–10 minutes with a 1:1 to 1:1.5 work-to-rest ratio. These efforts require recovery.
As you age, you still need high heart rate sessions. I’ve found running them can increase injury risk and recovery time, so I use the rowing machine. A 3–8 minute interval sends my heart rate soaring. Use whatever you like, the effort just needs to be hard.
For true fitness, think about your three-leg stool: strength, slow and steady, and VO2 work, then recover properly.
