why did my wifi usage jump by 1 mb from reading email for 43 minutes?

Hello @bobinnj 

Do you by any chance mean 1GB in your post? Because 1MB is not much and perfectly reasonable. I'm assuming you're asking about your cellular data usage. AT&T doesn't track how its users use data for privacy reasons, so there is no record of what applications or actions were used. Were there any graphics, attachments or videos in those emails?

Thanks,

Dmitriy