system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why I almost don't sweat while walking in a hot weather, but when I stop, sweating intensifies like 5 times.
gpt
Anaerobic respiration in certain types of muscle leads to something referred to as an oxygen debt. This primarily applies to fast twitch muscles (stronger) as opposed to slow twitch (endurance). 

Once you stop exercising, you start 'paying back' that oxygen debt, which generates heat. This extra heat combines with the hot weather to increase sweating. 

Watching professional short distance sprinting (say 200m) you frequently notice they cross the line with no visible sweat, but several minutes later have a distinct layer of sweat. 

This is also why you keep breathing heavily after you finish an exercise, your body still needs the oxygen to 'pay off' the debt.