<ol><li><a href="http://www.abstractsonline.com/pp8/#!/4196/presentation/8991">The most comprehensive study </a>came from Bryan Smith and his colleagues at Southern Illinois University Edwardsville. </li><li>They estimated VO2 max for 23 women and 26 men using the <a href="http://www.amazon.com/gp/product/B016PAPI3W/ref=as_li_tf_tl?ie=UTF8&linkCode=ogi&camp=1789&creative=9325&creativeASIN=B016PAPI3W&tag=runnersworld-auto-20&ascsubtag=[artid|2142.a.20856601[src|[ch|[lt|">Garmin 230</a>, <a href="http://www.amazon.com/gp/product/B018WBB750/ref=as_li_tf_tl?ie=UTF8&linkCode=ogi&camp=1789&creative=9325&creativeASIN=B018WBB750&tag=runnersworld-auto-20&ascsubtag=[artid|2142.a.20856601[src|[ch|[lt|">Garmin 235</a>, and <a href="http://www.amazon.com/gp/product/B01FRBB53M/ref=as_li_tf_tl?ie=UTF8&linkCode=ogi&camp=1789&creative=9325&creativeASIN=B01FRBB53M&tag=runnersworld-auto-20&ascsubtag=[artid|2142.a.20856601[src|[ch|[lt|">Polar V800</a>, then compared those results to gold-standard lab testing.</li><li>Typical VO2 max values in healthy college students tends to be in the 40s or 50s (in units of milliliters of oxygen per kilograms of body mass per minute). </li><li>Garmin measurements seem to consistently overestimate VO2 max, to a greater degree in men than women, and to a greater degree with the wrist sensor than the chest strap.</li></ol>

Garmin vs. Polar vs. Lab Tests

<ol><li>The best accurate test to measure your VO2 Max is still the lab test. </li><li>However, that's only necessary for elite athletes who want to improve their sports performance.</li><li>For general users who want to monitor general health and well-being, GPS watches that have the ability to measure VO2 Max would suffice - just bear in mind that the measurement is not 100% accurate, but good enough for personal monitoring.</li><li>GPS watches like Garmin compare your reading with other users of similar age group, gender and activity levels to indicate where your measurement stands in their statistics.</li></ol>

Conclusion 

<ol><li>Finally, <a href="http://www.abstractsonline.com/pp8/#!/4196/presentation/8953">Kent Johnson and Jenny Beadle of Lipscomb University</a> compared the values produced by Polar’s FT60 Fitness Test (the one based on heart-rate variability while lying down) with lab values in 31 subjects. </li><li>In this case, the average lab value was 44.9 ml/kg/min, and the Polar value was 49.8 ml/kg/min.</li><li>This overestimate of about 10 percent, or just under 5 ml/kg/min, is similar to what the Southern Illinois group saw in men, but not in women. </li><li>However, the Lipscomb volunteers were 13 men and 18 women, so that pattern of sex differences doesn’t seem consistent between the studies.</li></ol>

Polar vs. Lab Tests 

<ol><li>The best is to directly measure oxygen consumed while u exercise to exhaustion; eg. based on the distance during a 12-minute run.</li><li>There are also “sub-maximal” exercise protocols that estimate VO2 max based on your <a href="https://www.runnersworld.com/heart-rate/">heart rate</a> & pace, without forcing u to go all-out. This (along with basic information like your age and sex) is what some GPS watches do, by having u run for at least 10 minutes while simultaneously measuring your pace & heart rate.</li><li>There are also estimates that don’t involve exercise at all, but simply use information like your age, resting heart rate & activity levels.</li></ol>

How to Measure Your VO2 Max? 

<ol><li><a href="http://www.abstractsonline.com/pp8/#!/4196/presentation/8992">Another analysis</a> from the same group took a deeper head-to-head look at the data from the two Garmin systems.</li><li>Chest straps are considered highly accurate, and the wrist sensors produced heart rate values that were consistently lower than the chest strap. </li><li>That, in turn, meant that the wrist sensors overestimated VO2 max—which makes sense, since the heart-rate data was artificially low.</li><li>The conclusion, not surprisingly, is that chest straps give you better data. </li><li>The remaining question is whether the wrist band gives you “good enough” data, which depends on what you’re using it for.</li></ol>

Chest Strap vs. Wrist Sensor 

<ol><li><a href="http://www.abstractsonline.com/pp8/#!/4196/presentation/8449">Rebecca Moore and her colleagues at Eastern Michigan</a>, led by grad student Andrew Pearson, used a treadmill test and a Garmin Forerunner 235 (the one with the wrist sensor) to measure VO2 max in 23 volunteers.</li><li>In this case, the average VO2 max in the lab was 52.4 ml/kg/min, compared to 49.3 ml/kg/min with the watch—so the watch with the wrist sensor underestimated the lab value, which is the opposite of what the Southern Illinois study found.</li><li>The watch consistently underestimated VO2 max, particularly for those with higher values (above 50, a value generally found in sub-20:00 5K runners).</li></ol>

Garmin vs. Lab Tests

<ol><li>VO2 max is basically the definitive measurement of aerobic fitness. </li><li>It tells you the maximum rate at which you can take oxygen from the air and deliver through it through the lungs into the bloodstream for use by your working muscles. </li><li>It’s an excellent measurement of current health and predictor of future health—in fact, last fall the American Heart Association argued that it should <a href="https://www.runnersworld.com/health-injuries/a20836245/should-your-doctor-check-your-vo2-max/">classified as a new “vital sign”</a> to be assessed yearly by your doctor.</li></ol>

What is VO2 Max? 

<ol><li>The Polar measurements appear to be less accurate—not surprisingly, given that they’re estimating a characteristic of maximal exercise while at rest. </li><li>But the deviation seems to be completely different in men and women. </li><li>It’s hard to know whether this is an artifact of the particular group of men and women in this study (the men in the study had slightly higher BMIs and also slightly higher VO2 max), or something more systematic.</li></ol>

Garmin vs. Polar vs. Lab Tests (cont.) 

Four new studies test the accuracy of fitness prediction functions in advanced watches.