Any question answered...

ChatGPT can be very helpful...

asking it to "write a python program using the Garmin SDK to collect heart rate data from a chest strap at maximum sampling rate"

gives

Here's an example of a Python program that uses the Garmin SDK to collect heart rate data from a chest strap at maximum sampling rate:

import garmin_sdk

# Connect to the Garmin device
device = garmin_sdk.Client().get_devices()[0]

# Start the heart rate monitor
device.hrm_start()

# Get the maximum sampling rate
sampling_rate = device.hrm_get_sampling_rate()

# Collect the heart rate data
heart_rate_data = []
while True:
    heart_rate = device.hrm_get_heart_rate()
    heart_rate_data.append(heart_rate)
    time.sleep(1 / sampling_rate)

# Stop the heart rate monitor
device.hrm_stop()

# Save the collected data to a file
with open("heart_rate_data.txt", "w") as file:
    for data in heart_rate_data:
        file.write("%s\n" % data)

This code assumes that you have already installed the Garmin SDK and that you have a Garmin device connected to your computer. The garmin_sdk library is used to communicate with the device, and the hrm_start and hrm_stop methods are used to start and stop the heart rate monitor. The hrm_get_sampling_rate method is used to get the maximum sampling rate, and the hrm_get_heart_rate method is used to get the current heart rate. Finally, the collected data is saved to a file named heart_rate_data.txt.