Collecting the data is easy. Storing and transferring is harder.
What you need to is run the data collection in batches to save processing power for starters. I would look into what sampling rate you need. 24 hours is a long time for raw data especially sampling at 100hz.
Thats 1600 bytes per second on just the gyro or about 138mb per day. so thats about 280mb for just two sensors (which I dont know if you can do that large since the phone can't store data and I think holds it in ram?). They transfer the data via BLE which for 5mb takes me about 10 minutes. You can see how slow it is assuming no errors. Once you have the data collected on the fitbit watch you need think about transferring it. If you are using iphone you need to create a server on your computer with https certification that can handle PUT requests or http if you are on the same network. If you are using android you can host a server on your phone and use regular http. Unfortunately there is no way to simply access the data in a readable form without creating a server to transfer to first.
