Modified the sensor.py to something like that for another account:
# Sensor details.
SENSOR = 'google_fit_2'
# Sensor base attributes.
ATTR_LAST_UPDATED = 'last_updated'
CONF_CLIENT_ID = 'client_id'
CONF_CLIENT_SECRET = 'client_secret'
DEFAULT_NAME = 'Google Fit 2'
DEFAULT_CREDENTIALS_FILE = '.google_fit.credentials_2.json'
ICON = 'mdi:heart-pulse'
MIN_TIME_BETWEEN_SCANS = timedelta(minutes=10)
MIN_TIME_BETWEEN_UPDATES = timedelta(minutes=10)
TOKEN_FILE = '.{}.token'.format(SENSOR)
SENSOR_NAME = '{} {}'
and of course two separate sensors: one with platform: google_fit and another with google_fit_2 …
Best, JR