everyone's body is different, so it's impossible for me to generalize what others can handle. i have seen young guys clutch their chest in the gym and we have all seen videos of guys passing out after deadlifting.

but for me the key is to stay hydrated and to stay cool ( not overheat ).

some people advocate working out without AC, or using Sauna or Jacuzzi or some other source of heat ... but that is very dangerous. heat stroke can easily lead to death.

so can dehydration ( ask any UFC fighter - virtually all deaths in UFC are not from injuries in the cage, but from dehydration during cutting )

what i realized is that what most people believe is exhaustion is actually usually some combination of dehydration and overheating. if you manage those factors you can sustain higher intensity workouts for longer.

to avoid overheating train in a gym with good AC and use cool clothes. that means shorts and either microfiber shirt or a sleeveless tank.

as i explained earlier the reason many big guys wear hoodies isn't primarily to stay warm ( though some of them do like the heat ) but to avoid eye contact so that they won't get distracted by conversations and lose the pace and therefore the pump.