Since much of the data gathered with Google Fit is PII Category 0 health information, they do not provide direct access via an API (or at least not without a lot of faffing about).
You can, however, download the data via Google's 'Takeout' service, which will allow you access to pretty much everything Google has on you.
Once downloaded, unzip and play with the CSV to your heart's content :)
Running the Jupyter notebooks in Jupyter in PyCharm Community is painful.
pip install -r requirements.txt
python -m ipykernel install --user --name venv --display-name "Python3 (venv)"
jupyter notebook