The watch and ring disagree!

Question: I have a Garmin fenix 7 and an Oura ring, which do not always agree. An example is fitness age. Garmin shows 35 years, and Oura it is equal to my biological age minus 2 years. I am 79 years old, and I wonder what parameters are used to calculate fitness age? If there is such a big difference, I wonder if we can trust this data at all? VO max is calculated at 35 on my Garmin watch, but only 18 on my Oura ring. I have a baseline HRV of 66-89.

Answer: That is an interesting question. I actually went out and tried the Oura’s fitness test. Garmin gives me 45 in VO2 max and Oura gave me 39. I have previously tested VO 2 max on a treadmill and then it was only 0.5 in difference from the Garmin value. So here I probably trust Garmin the most. On my Garmin watch I get a fitness age that is 6 years younger than my chronological age and Oura gives me 1 year younger. I must say that I trust Garmin much more on these activity-related measurements. On the other hand, I trust Oura more on its sleep phase measurements.

Your watch, which gives you a fitness age of 35, is probably based on the old method from Garmin. That method is based on the fact that you have a fitness that is close to an average 35-year-old, despite your age. This is probably also reflected in your HRV, which is far higher than the average for your age. The new measurement calculations give a fitness age that is probably more realistic in relation to life expectancy. It’s not like you’re biologically 35 now and can expect to live another 55 years. Then you would be the oldest person in the world by a good margin.

Hope that was a helpful answer.

Best regards, Dr. Torkil