iosiphone
I'm planning on doing a new clean install of iOS 9 on my iPhone because I really like to have a clean slate when changing iPhones and upgrading iOS. However, the fact that Health, Activity, and Apple Watch data isn't synced to the cloud has made this difficult this year.
Is it possible to do a clean install of iOS 9 on my iPhone and also retain Health, Activity, and Apple Watch data? Or is it only possible to upgrade / restore from backup to keep that data?
Actually you can see your backup dates from settings local usage > watch.app
I went for a 2:30:00 run yesterday with my iPhone (6s) in my bag and my watch running strava. VO2max was recorded once per hour in three hours (10-11/11-12/12-13). I’ve tried to get VO2max off of shorter runs (5k-10k) on the same route without my phone but no data. I will now have to test longer runs with just watch and shorter ones with phone to get a definitive answer. Hope this is helpful. 
Best Answer
No, you cannot only restore Health data from a backup. Only encrypted iTunes backups and iCloud backups store Health.app data.