Neither... and both.
However, a new trainee should probably be asking him/herself, "Will every training session feel like this?" If your personal trainer or class instructor says "You're not really training hard- until you feel like you're going to puke." Run. Don't walk. Run away.
This is bogus in terms of the exercise science- and in no way fun.
Instead, realize that for the first several weeks of beginning a new exercise- strength and especially conditioning- program, your body might go through a bit of a break-through period in which you could feel sick, but feeling sick is in no way a requirement for results.
Stay Strong, Friends.
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