My first GET request always takes 27 seconds, after that every request takes only 1 second, Why?

The first time I execute a GET request for my specific api, It takes long time to get the response, after that no such delay.
When I try again after few hours, same scenario repeated exactly.

I used this script to calculate the response time:

var time = pm.response.responseTime
pm.test('Response time in seconds: ' + time / 1000)

First Get request: Response time in seconds: 26.721
Other Get requests (same api): Response time in seconds: 1.397

I am using postman 9.2.0 version. Can you please help me out.