The Fitness Motivator.
Motivated to run faster, many athletes focus on ways to improve VO2 Max levels. VO2 Max is the maximum amount of oxygen that our bodies can uptake and is measured as the quantity of oxygen per body weight over a set period of time. VO2 Max is affected by our heart’s volume per stroke, the total volume of blood in our system, and the hemoglobin’s ability to carry the oxygen.
So why would we care about improving what seems to be an arbitrary number? Our VO2 Max is a tell-tale sign of our level of conditioning. And while there are genetic factors that are not in our control, there are plenty of things we can do to improve VO2 Max and our level of performance along with it. By increasing the duration and intensity of our training, we will strengthen our heart, promote the growth of more capillaries in our muscles, reduce body fat levels, and increase our ability to perform better.
Levels of VO2 Max in a sedentary person can range from 20 ml/kg/min. to 50 ml/kg/min. Many elite endurance athletes have VO2 Max levels between 70 ml/kg/min and 90 ml/kg/min. Studies have shown that someone who is just starting to run can improve VO2 Max levels from 20-25% by building up their running routine to 25 miles per week. Runners that increase their weekly mileage from 25 miles per week to 50 miles per week can see an increase in VO2 Max of up to 10%...and the increase percentages get stingier from there for the advanced runners that increase their mileage above 50 miles per week. And while increases in mileage will continue to enhance our performance, it’s the speed workouts that will have the most lasting impact on VO2 Max levels.
Testing actual VO2 Max levels is done by taking blood and air volume samples at various points of exertion and exhaustion from an athlete during exercise. This can be expensive, tedious and unnecessary unless you’re a scientist or student with inexpensive access to a lab. It’s not critical that we know our actual VO2 Max “Number”, but figuring out our interval pace that will improve VO2 Max and performance level can be a definite benefit. So for the rest of us, here are some ways to determine our VO2 Max level & pace:
- VO2 Max Self Assessment – Balke Test
Many approximation tests like the Balke test involve a 15-minute time trial to determine our maximum oxygen uptake. On a calm and cool day, go to the nearest 400-meter track and run as many laps as you can in 15 minutes. Your estimated VO2 Max will equal 6.5 ml/kg/min + 5.0 ml/kg/min for every 400m lap that you can run in 15 minutes. So, for example, if you’re able to run 10 laps (2.5 miles or 4000 meters) in 15 minutes, your VO2 Max would be 56.5 ml/kg/min. You can use fractions (i.e “8.75 laps”) if interested in getting a more accurate approximation. This test and formula are deemed fairly accurate for those of us that run over 16:00 in the 5k…but please keep in mind that this is an approximation of your VO2 Max level only.
- Pace Estimation from 5k Race
Many workout and training guides will recommend that to improve VO2 Max levels, you should run intervals at a pace that’s 15-30 seconds faster than your 5k race pace. This can be a good indicator of your 100% VO2 Max pace if you have some recent race data to work with. Let’s say, for example, that your best 5K time is 21:42…that’s exactly a 7:00 per mile pace. If you want to run a VO2 Max interval workout, you’ll want to run at a pace of approximately 6:30 – 6:45, which for an 800-meter interval would be a goal time of 3:15 – 3:22 per interval (for this example).
- Correlation of Heart Rate & VO2 Max
If you regularly run with a heart rate monitor, this too can be an effective tool to find the right level of exertion to improve VO2 Max. It’s estimated that we reach 100% VO2 Max when our heart rate is in the 90-100% range of our Maximum Heart Rate (MHR). MHR can be estimated by subtracting our age from 220. Keep in mind that MHR is influenced by gender, conditioning, and other factors so it may vary. For example, I have never recorded a HR in any of my workouts over 95% of my MHR…so please don’t try to sustain an arbitrary heart rate for your workouts. Use good judgment. Compare your heart rate to that of some previous workouts at known paces, and hopefully you can decipher that heart rate that puts you in the 100% VO2 Max range. Personally, I’ve found my long easy distance runs are in the 70-80% MHR range, my lactate threshold runs are usually in the 80-88%MHR range, and my VO2 Max workouts are in the 88-95%MHR range. If your results differ, don’t worry. Everyone is different…don’t try too hard to fit the “text book” mold….it’s just a number ;-).
- Perceived Effort Scale
Many people use their relative perceived effort to gauge whether or not they’re running at the right pace. I find this to be a tad too subjective for my analytical liking, but it’s another means to help you refine your VO2 Max pace. The pace that will improve VO2 Max should feel like an 85-90% effort…not an all-out sprint, but a strenuous enough pace where conversation is near impossible. If your fastest interval time is the first one and your times get steadily slower as you run more repetitions…than you’re probably going too fast. If your times are consistent and you don’t need much of a recovery…you may be going to slow. Again, this is a difficult way to determine your VO2 Max pace, but when used with the other tools above it can serve as a good validation method.
When trying to conduct workouts that improve VO2 Max, try to sustain that pace for approximately 3-4 minutes, which can equate to intervals of 800-1000 meters. Using the example above (if your 5k PR = 21:42), you’ll want to plan your VO2 Max workout to run 800-meter intervals at a 3:15-3:20 pace. Initially try running 3-4 intervals that are 800-1000 meters long at your VO2 Max pace to start out with. As you progress, work up to 5-8 intervals. Take a 3-4 minute recovery walk/jog between intervals and make sure that the intervals, themselves, are run with some intensity…but not all out (use above rules-of-thumb for pace guidance). Because of the intensity and your body’s recovery & rebuild time needed, be sure that you limit VO2 Max workouts to once per week
If you are new to speed work or are just starting out in a running program, improving VO2 Max should take a back-seat to just building up of weekly mileage. In other words, focus your efforts on running comfortably for 30-45 minutes 4-5 times per week for several weeks before you start any serious speed work.
Because VO2 Max is measured as the actual maximum oxygen uptake per unit of body weight, we could also significantly improve VO2 Max by decreasing our body fat percentage. Notice that I didn’t say “decrease our weight”, because the loss of water and muscle weight will not benefit our performance…it will hurt it. So the silver lining of slimming down, could be some faster times! Keep that in mind when you reach for the cookie jar ;-).
Add mileage and intensity into your workouts once a week to improve VO2 Max. By increasing your aerobic capacity, you’ll see an improvement in your conditioning and your race times. See you at the track!
Start burning off that stuffing and pie now by training for Now I Can's 5K and fun run on May 14, 2011!