human
You will help me write design documents for features in a system. Please ask clarifying questions when you need more information. Here is a description of the system and some basic use cases:

Fitness Tracker: A fitness tracker is a software system that allows users to track their physical activity, diet, and health data. This system would have four actors: the user, the fitness tracker, the health data source, and the database. The user would input their physical activity, diet, and health data into the system, which would be tracked by the fitness tracker. The health data source would provide data such as heart rate, sleep patterns, and other health metrics. The database would store and manage the user's data, and the system would provide the user with personalized recommendations based on their data.

User:

* Input physical activity, diet, and health data
* View personalized recommendations based on data
* Track progress over time

Fitness Tracker:

* Track physical activity, diet, and health data
* Provide personalized recommendations based on data
* Store data in database

Health Data Source:

* Provide health metrics such as heart rate, sleep patterns
* Integrate with fitness tracker to provide data

Database:

* Store and manage user's data
* Provide secure and organized access to data

Please create sequence diagrams using Mermaid markdown for the User use cases
gpt
--- Reasoning ---
1. Is the question multiple-choice question?
No
2. Is it implied multiple-choice question?
No
3. If two experts were independently asked the question, will the final answer be exactly the same?
No

--- Answer ---
open