Why does crowded places make one feel tired?

scientific answer? well its easy to find out about the cause of being tired as what u said "" I am avoiding being crashed into, I am avoiding bumping into others, others are bumping sweaty elbows into me and knocking my handbag around""

1-by having this type of feeling seems like you are in a war , you are under stress, and u won't feel comfortable except if you are away of the crowd.

2-crowded places are often noisy, your brain my not accept noises as it cause stress

3-by looking at the crowed your eyes are extremely vigilant and looking to all passing by its also create stress

4-walking alone without having someone to talk to increase your stress as your attention is more focused on the crowed

there may have more things to take in consideration, weather,you body status i mean enough sleep or not, and the environment you are in here i mean do you feel safe or not?

sure you will tired if you never to turn all theses bad things to good , by changing the way you look at the crowed and to the noise and to each of the elements that cause you stress and tiredness

Maybe from struggle to change your situation, even if you aren't aware of it except for noticing tiredness. Meditating can help energize mind/body and make you healthier. You can still try to change whatever, but have less "struggle".

You could be an introvert or an empath, maybe both. Did you manage to find the answer you were looking for?

Could be anything from sensory overload, difficulty changing to your surroundings, or just plain introversion.

bcoz lack oxygen availability