The VO2 max interest: context, thoughts and an example applied test
- Apr 12, 2024
- 6 min read
Updated: Apr 7
Putting VO2 Max into some perspective:
Of late, fitness articles in the news indicate a growing interest in both performance and health-related VO2-max testing, which has been around since the 1920s. It has typically been a measure of the body’s metabolic engine (how much oxygen can the body utilize while physically alive, active and/or at-rest). VO2 max, a reference point as n outer parameter, can indicate measures of fitness, health, performance, etc. It is not, however, the be-all-and-end-all of fitness, health, performance, etc. Let me explain.
If some VO2 max improvement is good, should not a whole lot of improvement be even better? Too a point, it seems. Over the past few decades waves of research indicate that indicators like aerobics (VO2 max measures now getting mainstream attention), intentional mobility and muscle fitness (i.e., resistance or “strength training”, and even generalized, varied, and cumulative phsical activities, say within a day/week—all can improve health when judicially applied.
I had a 95 year old client who became virtually bed ridden for a couple of months, and was clinically frail. Having severe scoliosis (crooked spine), he was stuck looking down at his feet all the time. So, VO2 max/aerobic fitness was going to factor in, but was not the immediate concern. A number of exercise stragies were going have to go into play-- to regain making his own meals, walking around his apartment, leaving his apartment for various appointments and socials with his walker! He could not see 5 feet in front of his feet, so straightening his back was a priority. He was weakened from being in bed, so strengthening all his major joints was a priority. Overlapping these strength and mobility concerns, of course, getting him to move more, say, from one end of his apartment hallway to the other was going to be his VO2 max concerns.
Abilities to climb 5 flights of stairs used to be a cut-off for qualifying for certain types of surgeries. So, my client, Norman, with training, eventually qualified for such a task/test (with a much improved spine and ability to see his surroundings!).
Let’s try to get a handle on what VO2 max is: It measures the use of oxygen in primarily the muscles, and is calculated in terms of the muscle-machine’s leftover oxygen with the by-product carbon dioxide (exercising, the mask collects the two gases, and a machine measures the amounts of the gases). For perspective purposes, lets us use a 1-10 scale; 10 being the highest recorded scores by the rare few “elites” in the population. Norman was at the opposite end, frail: Frail persons could be categorized as 1-2 on our simple scale; or, to be technical, below 10 ml/kg/min (millilitres of oxygen utilized by a person's body part of one kilogram, within one minute) ; 6 ml/kg/min being extremely frail. The independent physically-able persons may be determined as 4-6 on the 1-10 scale. This grouping are might be considered potential health problems to our healthcare system. They might be assessed as the “needing improvement” or “fair” fitness.--at somewhere between 25-35 ml/kg/min. Seemingly not too picky, 35 ml/kg/min was not too long ago the minimal requirement for the Canadian Armed Forces non-combat personnel (6/10 on the rough scale). Vigorous persons of all ages could be anywhere from 35-55 ml/kg/min (7-9). The high end might be called excellent health-related fitness. The high end also allows for achieving impressive possibilities with performance tasks and having a vigorous, active lifestyle.
What about the elite VO2 max people? Are they guaranteed longer, healthier lives? If some VO2 max scores indicate better health outcomes, wouldn’t stratospheric score produce stratospheric health statuses?
Elite endurance athletes have been as high as 90 ml/kg/min (these persons are outliers; and they have been conditioned to such levels over the course of typically around at least a decade of training). They are also highly specialized. The elite runner at 90 ml/g/min would be noticeably less impressive on the bike test. And this number 90, although would be like a number 9/10 on the rough scale, certainly most people do not need to aspire to this level. This is where the hype about “longevity” needs to be discussed.
There is a concept called the J curve, a graph that shows adequate doses of a drug or exercise dose for the most and adequate outcomes. At a point the productive portion of the relation goes south, so to speak, showing a loss in efficacy. For most of us mortals the 90 ml/kg/min VO2 max dose would be an unhealthy goal. So, in terms of Olympic performance the elites are 9/10; and in terms of 55 ml/kg/min VO2 max for ages 19-85, that is excellent health and reasonable performance fitness (9/10) for the general population purposes.
Remember Norman, age 96, and frail. His mobility and applied strength was critical to do his daily tasks safely. Walking with his walker; standing and moving around the kitchen or bathroom or between his bed and the dresser drawers or closet required enough strength. Walking a block to the nearby cafe near his apartment was about as far as he might go. Going up a flight of stairs was realistic, three might be out of the question.
Can you see why strengthening the joints might be a better strategy to simply get Norman moving more, and more safely? Cardio and aerobic fitness is a by product. An important outcome no doubt.
However, are "elite" measures of VO2 max all that relevant? If some VO2 max improvement for my elderly client was so good, what about getting closer to the elite's level? For myself, I wish to attain and maintain an aerobic measurement that is typically suggestive of a soldier or a heavy industry worker. It might be equivalent to the aerobic/cardio vascular fitness of a healthy 19-29 year old male (tested to be in a "good" category).
One treadmill test that I am familiar with is through the Canadian Air Force, a Search and Rescue Technician personnel minimal standard aerobic fitness test. Passing this particular test is akin to a Very Good category for adult males. Think of the ability to play high school basketball,. It might be from 48-54 ml/kg/min. Remember 6 ml/kg/min is very frail, 90 ml/kg/min is the top endurance athlete. I simply wish to be robust enough to have a great chance for more adventures into old age. My ideal. 90 ml/kg/min is not in the cards, and that kind of goal, for me might be too hard albeit too harsh.
I have overall strength and mobility to entertain this kind of standard--for now. It is realistic. And it can be reached without undue discomfort in a training plan. The Canadian Search and Rescue treadmill test has a 21 minute minimal duration at 3.5 mph, carrying a 55 lb pack. First 6 minutes serve as a warm-up; going from a two degree incline, to four, and then 6 degrees. The next 15 minutes are at 8 degrees (3.5 mph). If completed to this point (total 21 minutes)--a pass mark is given. The further testing involves a degree increase each subsequent minute--up to 15 degrees. Even further fitness involves staying at 15 degrees while adding .5 mph with each subsequent minute. 33 minutes is top performance, 30 is the organization's average.
Years ago, I had a Canadian Coast Guard officer as an insurance case (knee rehab and fitness). My reports refer to this Canadian search and rescue test passing cut-off as being an approximate VO2 max of 48 ml/kg/min.
The minimum 21 minute pass mark is what I am training at this point. By July 1, I will likely lose 10-15 lbs, and the present 35 lb pack will increase to 55 lb by then. Summer brings more opportunities to go mountain hiking with a pack. Summer ocean swimming and increased biking also helps bring down the body fat.
The Norwegian test is in a separate post: Note the speed of this test compared to the Canadian one described above.
My more challenging training program(s) at various time in the past coupe of years:
6 x 300 m up hill and back down hill with 40 lb pack (6x 600 m=3600 m); jog up, walk down
2 x 3000 m walk with 40 lb pack (one hour rest between 3000 m walks)
5 x 300 m hill and back (no pack); up hill, 30 sec jog to 20 sec run to 10 sec spring; walk down hill OR
8 x one minute heavy breath followed by one minute recovery walk--on relatively flat soft trail
These would be considered 'Hard' days for me!
Supplement aerobic development includes swims of 400 m, bike 6-12 k, easy jogs and brisk walks most days of the week
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