[Bug] Average number of days of activity is wrong

6346938 said:

the average number of days of activity for the last 6 weeks

AFAIK, there is no such thing as the average number of days of activity as a factor in Fitness Age. Perhaps you mistake with Vigorous Days, ain't you? Those are unrelated to Activities (at least not directly). A week counts as "vigorous" if you get at least 5 consecutive Vigorous Intensity Minutes at least 3 days a week.

You are right, I am talking about days of vigorous activitiy. The conclusion remains the same. With 3 days per week for more than 6 weeks, the average calculated is 2.8 instead of 3. There is a bug somewhere.

Perhaps you just do not have as many vigorous days as you believe. It is not easy to guess just by looking at the IM stats, since there have to be 5 continuous vigorous minutes in the day, in order that the day counts as vigorous, and you won't see it on the IM screen. Individual, separated vigorous minutes do not count, although you see them in the IM totals for any given day.

Each time I go running it records at least 30 minutes of vigorous activity. I have done so 3 days per week for more than the last 6 weeks.

6346938 said:

Each time I go running it records at least 30 minutes of vigorous activity.

It does not mean yet there are any 5 continuous vigorous IMs. You'd have to post the complete data for all the 6 weeks, otherwise we can only guess where the problem is. However, I do not think their algorithm is wrong. Maybe you just need to be more active. I have usually the average of around 6 vigorous days per week (mostly 7), but I run, swim, bike, and do also other types of sport daily, so I know I can easily get over the required threshold. Running just 3 times a week and doing nothing else, may simply not be sufficient. And it sounds reasonable.