If possible, arrange cover for your time away from your desk. At the least, leave a voicemail and “out of office” email response, so people know you're at training. Make sure key people know you won't be there, and ask them not to leave urgent matters or tasks on your desk. If you know something important or urgent is expected while you're training, make sure you arrange someone to deal with it, even if that's your manager. Treat your colleagues' needs and timetable professionally, and they'll respect your training time all the more.